ubuntu-cve-2026-63073
Vulnerability from osv_ubuntu
Published
2026-08-25 00:00
Modified
2026-09-02 16:20
Summary
Details
Issue summary: OpenSSL CMP response validation passed an unexpected response sender distinguished name directly as the format string to ERR_raise_data(). Impact summary: A malicious or intercepted CMP endpoint can crash a CMP client that enforces an expected sender or uses a pinned server certificate whose subject becomes the default expected sender. CWE: CWE-134 (Use of Externally-Controlled Format String) Description: When validating a received CMP message, ossl_cmp_msg_check_update() converts the peer-supplied sender distinguished name with X509_NAME_oneline() and passes it directly as the format argument to ERR_raise_data(). Percent characters survive the conversion, so a sender DN such as "CN=%s%n" reaches BIO_vsnprintf() as an attacker-controlled format string with no matching variadic arguments. This path is only reached when the caller configures an expected sender or pins a server certificate, which is the normal configuration for a CMP client validating server responses. Since the attacker controls the format string but none of the variadic arguments, such specifiers as %s and %n dereference or write through unrelated stack contents and crash the client. The reliable consequence is a denial of service, when the response comes from a malicious or intercepted CMP endpoint. There is no controlled memory write, arbitrary-address read, or reliable path to remote code execution. FIPS impact: no No FIPS modules are affected by this issue, as the CMP protocol implementation is outside the OpenSSL FIPS module boundary.
Severity
9.8 (Critical)
N/A (UNKNOWN)
References
| URL | Type | |
|---|---|---|
{
"affected": [
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "nodejs",
"binary_version": "4.2.6~dfsg-1ubuntu4.2+esm3"
},
{
"binary_name": "nodejs-legacy",
"binary_version": "4.2.6~dfsg-1ubuntu4.2+esm3"
}
],
"priority_reason": "OpenSSL developers have rated this low severity"
},
"package": {
"ecosystem": "Ubuntu:Pro:16.04:LTS",
"name": "nodejs",
"purl": "pkg:deb/ubuntu/nodejs@4.2.6~dfsg-1ubuntu4.2+esm3?arch=source\u0026distro=esm-apps/xenial"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"0.10.25~dfsg2-2ubuntu1",
"4.2.2~dfsg-1",
"4.2.3~dfsg-1",
"4.2.4~dfsg-1ubuntu1",
"4.2.4~dfsg-2",
"4.2.6~dfsg-1ubuntu1",
"4.2.6~dfsg-1ubuntu4",
"4.2.6~dfsg-1ubuntu4.1",
"4.2.6~dfsg-1ubuntu4.2",
"4.2.6~dfsg-1ubuntu4.2+esm1",
"4.2.6~dfsg-1ubuntu4.2+esm2",
"4.2.6~dfsg-1ubuntu4.2+esm3"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "nodejs",
"binary_version": "8.10.0~dfsg-2ubuntu0.4+esm6"
}
],
"priority_reason": "OpenSSL developers have rated this low severity"
},
"package": {
"ecosystem": "Ubuntu:Pro:18.04:LTS",
"name": "nodejs",
"purl": "pkg:deb/ubuntu/nodejs@8.10.0~dfsg-2ubuntu0.4+esm6?arch=source\u0026distro=esm-apps/bionic"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"6.11.4~dfsg-1ubuntu1",
"6.11.4~dfsg-1ubuntu2",
"6.12.0~dfsg-1ubuntu1",
"6.12.0~dfsg-2ubuntu1",
"6.12.0~dfsg-2ubuntu2",
"8.10.0~dfsg-2",
"8.10.0~dfsg-2ubuntu0.2",
"8.10.0~dfsg-2ubuntu0.3",
"8.10.0~dfsg-2ubuntu0.4",
"8.10.0~dfsg-2ubuntu0.4+esm1",
"8.10.0~dfsg-2ubuntu0.4+esm2",
"8.10.0~dfsg-2ubuntu0.4+esm3",
"8.10.0~dfsg-2ubuntu0.4+esm4",
"8.10.0~dfsg-2ubuntu0.4+esm5",
"8.10.0~dfsg-2ubuntu0.4+esm6"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "openssl-fips-module-3",
"binary_version": "3.0.5-0ubuntu0.1+Fips2.1"
}
],
"priority_reason": "OpenSSL developers have rated this low severity"
},
"package": {
"ecosystem": "Ubuntu:Pro:FIPS-preview:22.04:LTS",
"name": "openssl-fips",
"purl": "pkg:deb/ubuntu/openssl-fips@3.0.5-0ubuntu0.1+Fips2.1?arch=source\u0026distro=fips-preview/jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.0.5-0ubuntu0.1+Fips2.1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "openssl-fips-module-3",
"binary_version": "3.0.5-0ubuntu0.2+Fips1"
}
],
"priority_reason": "OpenSSL developers have rated this low severity"
},
"package": {
"ecosystem": "Ubuntu:Pro:FIPS-updates:22.04:LTS",
"name": "openssl-fips",
"purl": "pkg:deb/ubuntu/openssl-fips@3.0.5-0ubuntu0.2+Fips1?arch=source\u0026distro=fips-updates/jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.0.5-0ubuntu0.1+Fips2.1",
"3.0.5-0ubuntu0.2+Fips1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "openssl-fips-module-3",
"binary_version": "3.0.13-0ubuntu3.15+Fips1"
}
],
"priority_reason": "OpenSSL developers have rated this low severity"
},
"package": {
"ecosystem": "Ubuntu:Pro:FIPS-updates:24.04:LTS",
"name": "openssl-fips",
"purl": "pkg:deb/ubuntu/openssl-fips@3.0.13-0ubuntu3.15+Fips1?arch=source\u0026distro=fips-updates/noble"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.0.13-0ubuntu3+Fips1",
"3.0.13-0ubuntu3.6+Fips1",
"3.0.13-0ubuntu3.12+Fips1",
"3.0.13-0ubuntu3.15+Fips1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "efi-shell-aa64",
"binary_version": "2025.11-3ubuntu7"
},
{
"binary_name": "efi-shell-loongarch64",
"binary_version": "2025.11-3ubuntu7"
},
{
"binary_name": "efi-shell-riscv64",
"binary_version": "2025.11-3ubuntu7"
},
{
"binary_name": "efi-shell-x64",
"binary_version": "2025.11-3ubuntu7"
},
{
"binary_name": "ovmf",
"binary_version": "2025.11-3ubuntu7"
},
{
"binary_name": "ovmf-amdsev",
"binary_version": "2025.11-3ubuntu7"
},
{
"binary_name": "ovmf-generic",
"binary_version": "2025.11-3ubuntu7"
},
{
"binary_name": "ovmf-inteltdx",
"binary_version": "2025.11-3ubuntu7"
},
{
"binary_name": "ovmf-legacy",
"binary_version": "2025.11-3ubuntu7"
},
{
"binary_name": "qemu-efi-aarch64",
"binary_version": "2025.11-3ubuntu7"
},
{
"binary_name": "qemu-efi-loongarch64",
"binary_version": "2025.11-3ubuntu7"
},
{
"binary_name": "qemu-efi-riscv64",
"binary_version": "2025.11-3ubuntu7"
}
],
"priority_reason": "OpenSSL developers have rated this low severity"
},
"package": {
"ecosystem": "Ubuntu:26.04:LTS",
"name": "edk2",
"purl": "pkg:deb/ubuntu/edk2@2025.11-3ubuntu7?arch=source\u0026distro=resolute"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2025.02-8ubuntu3",
"2025.11-3ubuntu6",
"2025.11-3ubuntu7"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "efi-shell-aa64-hwe",
"binary_version": "2025.11-3ubuntu8"
},
{
"binary_name": "efi-shell-loongarch64-hwe",
"binary_version": "2025.11-3ubuntu8"
},
{
"binary_name": "efi-shell-riscv64-hwe",
"binary_version": "2025.11-3ubuntu8"
},
{
"binary_name": "efi-shell-x64-hwe",
"binary_version": "2025.11-3ubuntu8"
},
{
"binary_name": "ovmf-amdsev-hwe",
"binary_version": "2025.11-3ubuntu8"
},
{
"binary_name": "ovmf-generic-hwe",
"binary_version": "2025.11-3ubuntu8"
},
{
"binary_name": "ovmf-hwe",
"binary_version": "2025.11-3ubuntu8"
},
{
"binary_name": "ovmf-inteltdx-hwe",
"binary_version": "2025.11-3ubuntu8"
},
{
"binary_name": "ovmf-legacy-hwe",
"binary_version": "2025.11-3ubuntu8"
},
{
"binary_name": "qemu-efi-aarch64-hwe",
"binary_version": "2025.11-3ubuntu8"
},
{
"binary_name": "qemu-efi-loongarch64-hwe",
"binary_version": "2025.11-3ubuntu8"
},
{
"binary_name": "qemu-efi-riscv64-hwe",
"binary_version": "2025.11-3ubuntu8"
}
],
"priority_reason": "OpenSSL developers have rated this low severity"
},
"package": {
"ecosystem": "Ubuntu:26.04:LTS",
"name": "edk2-hwe",
"purl": "pkg:deb/ubuntu/edk2-hwe@2025.11-3ubuntu8?arch=source\u0026distro=resolute"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2025.11-3ubuntu6",
"2025.11-3ubuntu8"
]
},
{
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "libssl3t64",
"binary_version": "3.5.5-1ubuntu3.4"
},
{
"binary_name": "openssl",
"binary_version": "3.5.5-1ubuntu3.4"
},
{
"binary_name": "openssl-provider-legacy",
"binary_version": "3.5.5-1ubuntu3.4"
}
],
"priority_reason": "OpenSSL developers have rated this low severity"
},
"package": {
"ecosystem": "Ubuntu:26.04:LTS",
"name": "openssl",
"purl": "pkg:deb/ubuntu/openssl@3.5.5-1ubuntu3.4?arch=source\u0026distro=resolute"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "3.5.5-1ubuntu3.4"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.5.3-1ubuntu2",
"3.5.5-1ubuntu1",
"3.5.5-1ubuntu3",
"3.5.5-1ubuntu3.2",
"3.5.5-1ubuntu3.3"
]
}
],
"aliases": [],
"details": "Issue summary: OpenSSL CMP response validation passed an unexpected response sender distinguished name directly as the format string to `ERR_raise_data()`. Impact summary: A malicious or intercepted CMP endpoint can crash a CMP client that enforces an expected sender or uses a pinned server certificate whose subject becomes the default expected sender. CWE: CWE-134 (Use of Externally-Controlled Format String) Description: When validating a received CMP message, ossl_cmp_msg_check_update() converts the peer-supplied sender distinguished name with X509_NAME_oneline() and passes it directly as the format argument to ERR_raise_data(). Percent characters survive the conversion, so a sender DN such as \"CN=%s%n\" reaches BIO_vsnprintf() as an attacker-controlled format string with no matching variadic arguments. This path is only reached when the caller configures an expected sender or pins a server certificate, which is the normal configuration for a CMP client validating server responses. Since the attacker controls the format string but none of the variadic arguments, such specifiers as %s and %n dereference or write through unrelated stack contents and crash the client. The reliable consequence is a denial of service, when the response comes from a malicious or intercepted CMP endpoint. There is no controlled memory write, arbitrary-address read, or reliable path to remote code execution. FIPS impact: no No FIPS modules are affected by this issue, as the CMP protocol implementation is outside the OpenSSL FIPS module boundary.",
"id": "UBUNTU-CVE-2026-63073",
"modified": "2026-09-02T16:20:05Z",
"published": "2026-08-25T00:00:00Z",
"references": [
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-63073"
},
{
"type": "REPORT",
"url": "https://www.cve.org/CVERecord?id=CVE-2026-63073"
},
{
"type": "ADVISORY",
"url": "https://ubuntu.com/security/notices/USN-8678-1"
}
],
"related": [
"USN-8678-1"
],
"schema_version": "1.7.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "low",
"type": "Ubuntu"
}
],
"upstream": [
"CVE-2026-63073"
]
}
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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.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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