RHSA-2026:25520
Vulnerability from csaf_redhat - Published: 2026-06-12 13:47 - Updated: 2026-06-18 16:05Summary
Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update
Severity
Moderate
Notes
Topic: An update for Red Hat Hardened Images RPMs is now available.
Details: This update includes the following RPMs:
krb5:
* krb5-devel-1.22.2-8.hum1 (aarch64, x86_64)
* krb5-libs-1.22.2-8.hum1 (aarch64, x86_64)
* krb5-pkinit-1.22.2-8.hum1 (aarch64, x86_64)
* krb5-server-1.22.2-8.hum1 (aarch64, x86_64)
* krb5-server-ldap-1.22.2-8.hum1 (aarch64, x86_64)
* krb5-tests-1.22.2-8.hum1 (aarch64, x86_64)
* krb5-workstation-1.22.2-8.hum1 (aarch64, x86_64)
* krb5-xrealmauthz-1.22.2-8.hum1 (aarch64, x86_64)
* libkadm5-1.22.2-8.hum1 (aarch64, x86_64)
* krb5-1.22.2-8.hum1.src (src)
Security Fix(es):
krb5:
* CVE-2026-11850
Terms of Use: This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original.
An integer underflow vulnerability was found in MIT krb5 in the berval2tl_data() function in plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c. The function performs an unsigned subtraction (bv_len - 2) without a prior bounds check. When bv_len is 0 or 1, the subtraction wraps to a large value which is then truncated to uint16_t, yielding 0xFFFE (65534) or 0xFFFF (65535). The subsequent malloc succeeds and memcpy reads up to 65534 bytes from a 0-1 byte buffer, resulting in a heap out-of-bounds read. The attack vector involves a malicious or compromised LDAP KDB backend returning a krbExtraData attribute with bv_len < 2, triggering the underflow when the KDC or kadmind reads principal data.
5.0 (Medium)
Affected products
Fixed
3 products
| Product | Identifier | Version | Remediation |
|---|---|---|---|
| Unresolved product id: Red Hat Hardened Images:krb5-main@aarch64 | — |
Vendor Fix
fix
Workaround
|
|
| Unresolved product id: Red Hat Hardened Images:krb5-main@src | — |
Vendor Fix
fix
Workaround
|
|
| Unresolved product id: Red Hat Hardened Images:krb5-main@x86_64 | — |
Vendor Fix
fix
Workaround
|
Threats
Impact
Moderate
References
9 references
Acknowledgments
Sebastián Alba Vives
{
"document": {
"aggregate_severity": {
"namespace": "https://access.redhat.com/security/updates/classification/",
"text": "Moderate"
},
"category": "csaf_security_advisory",
"csaf_version": "2.0",
"distribution": {
"text": "Copyright \u00a9 Red Hat, Inc. All rights reserved.",
"tlp": {
"label": "WHITE",
"url": "https://www.first.org/tlp/"
}
},
"lang": "en",
"notes": [
{
"category": "summary",
"text": "An update for Red Hat Hardened Images RPMs is now available.",
"title": "Topic"
},
{
"category": "general",
"text": "This update includes the following RPMs:\n\nkrb5:\n * krb5-devel-1.22.2-8.hum1 (aarch64, x86_64)\n * krb5-libs-1.22.2-8.hum1 (aarch64, x86_64)\n * krb5-pkinit-1.22.2-8.hum1 (aarch64, x86_64)\n * krb5-server-1.22.2-8.hum1 (aarch64, x86_64)\n * krb5-server-ldap-1.22.2-8.hum1 (aarch64, x86_64)\n * krb5-tests-1.22.2-8.hum1 (aarch64, x86_64)\n * krb5-workstation-1.22.2-8.hum1 (aarch64, x86_64)\n * krb5-xrealmauthz-1.22.2-8.hum1 (aarch64, x86_64)\n * libkadm5-1.22.2-8.hum1 (aarch64, x86_64)\n * krb5-1.22.2-8.hum1.src (src)\n\nSecurity Fix(es):\n\nkrb5:\n * CVE-2026-11850",
"title": "Details"
},
{
"category": "legal_disclaimer",
"text": "This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original.",
"title": "Terms of Use"
}
],
"publisher": {
"category": "vendor",
"contact_details": "https://access.redhat.com/security/team/contact/",
"issuing_authority": "Red Hat Product Security is responsible for vulnerability handling across all Red Hat products and services.",
"name": "Red Hat Product Security",
"namespace": "https://www.redhat.com"
},
"references": [
{
"category": "self",
"summary": "https://access.redhat.com/errata/RHSA-2026:25520",
"url": "https://access.redhat.com/errata/RHSA-2026:25520"
},
{
"category": "external",
"summary": "https://access.redhat.com/security/cve/CVE-2026-11850",
"url": "https://access.redhat.com/security/cve/CVE-2026-11850"
},
{
"category": "external",
"summary": "https://access.redhat.com/security/updates/classification/",
"url": "https://access.redhat.com/security/updates/classification/"
},
{
"category": "external",
"summary": "https://images.redhat.com/",
"url": "https://images.redhat.com/"
},
{
"category": "self",
"summary": "Canonical URL",
"url": "https://security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_25520.json"
}
],
"title": "Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update",
"tracking": {
"current_release_date": "2026-06-18T16:05:36+00:00",
"generator": {
"date": "2026-06-18T16:05:36+00:00",
"engine": {
"name": "Red Hat SDEngine",
"version": "5.0.0"
}
},
"id": "RHSA-2026:25520",
"initial_release_date": "2026-06-12T13:47:06+00:00",
"revision_history": [
{
"date": "2026-06-12T13:47:06+00:00",
"number": "1",
"summary": "Initial version"
},
{
"date": "2026-06-12T13:50:46+00:00",
"number": "2",
"summary": "Last updated version"
},
{
"date": "2026-06-18T16:05:36+00:00",
"number": "3",
"summary": "Last generated version"
}
],
"status": "final",
"version": "3"
}
},
"product_tree": {
"branches": [
{
"branches": [
{
"branches": [
{
"category": "product_name",
"name": "Red Hat Hardened Images",
"product": {
"name": "Red Hat Hardened Images",
"product_id": "Red Hat Hardened Images",
"product_identification_helper": {
"cpe": "cpe:/a:redhat:hummingbird:1"
}
}
}
],
"category": "product_family",
"name": "Red Hat Hardened Images"
},
{
"branches": [
{
"category": "product_version",
"name": "krb5-main@src",
"product": {
"name": "krb5-main@src",
"product_id": "krb5-main@src",
"product_identification_helper": {
"purl": "pkg:rpm/redhat/krb5@1.22.2-8.hum1?arch=src\u0026distro=hummingbird-20251124\u0026repository_id=public-hummingbird-source-rpms"
}
}
}
],
"category": "architecture",
"name": "src"
},
{
"branches": [
{
"category": "product_version",
"name": "krb5-main@aarch64",
"product": {
"name": "krb5-main@aarch64",
"product_id": "krb5-main@aarch64",
"product_identification_helper": {
"purl": "pkg:rpm/redhat/krb5-devel@1.22.2-8.hum1?arch=aarch64\u0026distro=hummingbird-20251124\u0026repository_id=public-hummingbird-aarch64-rpms"
}
}
}
],
"category": "architecture",
"name": "aarch64"
},
{
"branches": [
{
"category": "product_version",
"name": "krb5-main@x86_64",
"product": {
"name": "krb5-main@x86_64",
"product_id": "krb5-main@x86_64",
"product_identification_helper": {
"purl": "pkg:rpm/redhat/krb5-devel@1.22.2-8.hum1?arch=x86_64\u0026distro=hummingbird-20251124\u0026repository_id=public-hummingbird-x86_64-rpms"
}
}
}
],
"category": "architecture",
"name": "x86_64"
}
],
"category": "vendor",
"name": "Red Hat"
}
],
"relationships": [
{
"category": "default_component_of",
"full_product_name": {
"name": "krb5-main@aarch64 as a component of Red Hat Hardened Images",
"product_id": "Red Hat Hardened Images:krb5-main@aarch64"
},
"product_reference": "krb5-main@aarch64",
"relates_to_product_reference": "Red Hat Hardened Images"
},
{
"category": "default_component_of",
"full_product_name": {
"name": "krb5-main@src as a component of Red Hat Hardened Images",
"product_id": "Red Hat Hardened Images:krb5-main@src"
},
"product_reference": "krb5-main@src",
"relates_to_product_reference": "Red Hat Hardened Images"
},
{
"category": "default_component_of",
"full_product_name": {
"name": "krb5-main@x86_64 as a component of Red Hat Hardened Images",
"product_id": "Red Hat Hardened Images:krb5-main@x86_64"
},
"product_reference": "krb5-main@x86_64",
"relates_to_product_reference": "Red Hat Hardened Images"
}
]
},
"vulnerabilities": [
{
"acknowledgments": [
{
"names": [
"Sebasti\u00e1n Alba Vives"
]
}
],
"cve": "CVE-2026-11850",
"cwe": {
"id": "CWE-191",
"name": "Integer Underflow (Wrap or Wraparound)"
},
"discovery_date": "2026-04-21T00:00:00+00:00",
"ids": [
{
"system_name": "Red Hat Bugzilla ID",
"text": "2459970"
}
],
"notes": [
{
"category": "description",
"text": "An integer underflow vulnerability was found in MIT krb5 in the berval2tl_data() function in plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c. The function performs an unsigned subtraction (bv_len - 2) without a prior bounds check. When bv_len is 0 or 1, the subtraction wraps to a large value which is then truncated to uint16_t, yielding 0xFFFE (65534) or 0xFFFF (65535). The subsequent malloc succeeds and memcpy reads up to 65534 bytes from a 0-1 byte buffer, resulting in a heap out-of-bounds read.\nThe attack vector involves a malicious or compromised LDAP KDB backend returning a krbExtraData attribute with bv_len \u003c 2, triggering the underflow when the KDC or kadmind reads principal data.",
"title": "Vulnerability description"
},
{
"category": "summary",
"text": "krb5: krb5: integer underflow in berval2tl_data() leads to heap out-of-bounds read",
"title": "Vulnerability summary"
},
{
"category": "other",
"text": "Red Hat rates this issue as Moderate impact. In krb5\u0027s LDAP KDB plugin, berval2tl_data() subtracts two from a BER value length without checking it is at least two. A malicious or compromised LDAP KDB backend returning krbExtraData with length 0 or 1 causes unsigned underflow and a large heap out-of-bounds read when the KDC or kadmind loads principal data. Exploitation requires compromise of or write access to the LDAP backend used as the Kerberos database. Deployments using file-based KDB backends rather than LDAP are not affected by this code path.",
"title": "Statement"
},
{
"category": "general",
"text": "The CVSS score(s) listed for this vulnerability do not reflect the associated product\u0027s status, and are included for informational purposes to better understand the severity of this vulnerability.",
"title": "CVSS score applicability"
}
],
"product_status": {
"fixed": [
"Red Hat Hardened Images:krb5-main@aarch64",
"Red Hat Hardened Images:krb5-main@src",
"Red Hat Hardened Images:krb5-main@x86_64"
]
},
"references": [
{
"category": "self",
"summary": "Canonical URL",
"url": "https://access.redhat.com/security/cve/CVE-2026-11850"
},
{
"category": "external",
"summary": "RHBZ#2459970",
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2459970"
},
{
"category": "external",
"summary": "https://www.cve.org/CVERecord?id=CVE-2026-11850",
"url": "https://www.cve.org/CVERecord?id=CVE-2026-11850"
},
{
"category": "external",
"summary": "https://nvd.nist.gov/vuln/detail/CVE-2026-11850",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-11850"
}
],
"release_date": "2026-06-10T00:00:00+00:00",
"remediations": [
{
"category": "vendor_fix",
"date": "2026-06-12T13:47:06+00:00",
"details": "For details on how to apply this update, which includes the changes described in this advisory, refer to:\nhttps://images.redhat.com/",
"product_ids": [
"Red Hat Hardened Images:krb5-main@aarch64",
"Red Hat Hardened Images:krb5-main@src",
"Red Hat Hardened Images:krb5-main@x86_64"
],
"restart_required": {
"category": "none"
},
"url": "https://access.redhat.com/errata/RHSA-2026:25520"
},
{
"category": "workaround",
"details": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.",
"product_ids": [
"Red Hat Hardened Images:krb5-main@aarch64",
"Red Hat Hardened Images:krb5-main@src",
"Red Hat Hardened Images:krb5-main@x86_64"
]
}
],
"scores": [
{
"cvss_v3": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 5.0,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "LOW",
"integrityImpact": "NONE",
"privilegesRequired": "HIGH",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H",
"version": "3.1"
},
"products": [
"Red Hat Hardened Images:krb5-main@aarch64",
"Red Hat Hardened Images:krb5-main@src",
"Red Hat Hardened Images:krb5-main@x86_64"
]
}
],
"threats": [
{
"category": "impact",
"details": "Moderate"
}
],
"title": "krb5: krb5: integer underflow in berval2tl_data() leads to heap out-of-bounds read"
}
]
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Loading…
Loading…