CVE-2026-43405 (GCVE-0-2026-43405)
Vulnerability from cvelistv5 – Published: 2026-05-08 14:21 – Updated: 2026-05-09 04:10
VLAI?
Title
libceph: Use u32 for non-negative values in ceph_monmap_decode()
Summary
In the Linux kernel, the following vulnerability has been resolved:
libceph: Use u32 for non-negative values in ceph_monmap_decode()
This patch fixes unnecessary implicit conversions that change signedness
of blob_len and num_mon in ceph_monmap_decode().
Currently blob_len and num_mon are (signed) int variables. They are used
to hold values that are always non-negative and get assigned in
ceph_decode_32_safe(), which is meant to assign u32 values. Both
variables are subsequently used as unsigned values, and the value of
num_mon is further assigned to monmap->num_mon, which is of type u32.
Therefore, both variables should be of type u32. This is especially
relevant for num_mon. If the value read from the incoming message is
very large, it is interpreted as a negative value, and the check for
num_mon > CEPH_MAX_MON does not catch it. This leads to the attempt to
allocate a very large chunk of memory for monmap, which will most likely
fail. In this case, an unnecessary attempt to allocate memory is
performed, and -ENOMEM is returned instead of -EINVAL.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
| Vendor | Product | Version | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux |
Affected:
a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c , < ee5588e2bc41acb73f6676c0520420c107cd0140
(git)
Affected: a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c , < 86f7060cd638d6eb042e8ed780fb83a59ca0dcb3 (git) Affected: a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c , < 5f2806684b05bd24d05c091083b8e2517ba8ffac (git) Affected: a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c , < b268984ae88cb0dcd7a8e8263962c748448e26e8 (git) Affected: a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c , < ba0a4df8c563536857dcbf7b4dbd0f2a15f57ace (git) Affected: a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c , < 08bc6173fd611ad5a40f472bf5f15b92aea0fe40 (git) Affected: a5cbd5fc22d5043a8a76e15d75d031fe24d1f69c , < 770444611f047dbfd4517ec0bc1b179d40c2f346 (git) |
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|
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{
"containers": {
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"programFiles": [
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"versionType": "git"
}
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},
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],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"versions": [
{
"status": "affected",
"version": "5.11"
},
{
"lessThan": "5.11",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.203",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.167",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.130",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.78",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.19",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.19.9",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
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"nodes": [
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}
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"negate": false,
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],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: Use u32 for non-negative values in ceph_monmap_decode()\n\nThis patch fixes unnecessary implicit conversions that change signedness\nof blob_len and num_mon in ceph_monmap_decode().\nCurrently blob_len and num_mon are (signed) int variables. They are used\nto hold values that are always non-negative and get assigned in\nceph_decode_32_safe(), which is meant to assign u32 values. Both\nvariables are subsequently used as unsigned values, and the value of\nnum_mon is further assigned to monmap-\u003enum_mon, which is of type u32.\nTherefore, both variables should be of type u32. This is especially\nrelevant for num_mon. If the value read from the incoming message is\nvery large, it is interpreted as a negative value, and the check for\nnum_mon \u003e CEPH_MAX_MON does not catch it. This leads to the attempt to\nallocate a very large chunk of memory for monmap, which will most likely\nfail. In this case, an unnecessary attempt to allocate memory is\nperformed, and -ENOMEM is returned instead of -EINVAL."
}
],
"providerMetadata": {
"dateUpdated": "2026-05-09T04:10:50.413Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/ee5588e2bc41acb73f6676c0520420c107cd0140"
},
{
"url": "https://git.kernel.org/stable/c/86f7060cd638d6eb042e8ed780fb83a59ca0dcb3"
},
{
"url": "https://git.kernel.org/stable/c/5f2806684b05bd24d05c091083b8e2517ba8ffac"
},
{
"url": "https://git.kernel.org/stable/c/b268984ae88cb0dcd7a8e8263962c748448e26e8"
},
{
"url": "https://git.kernel.org/stable/c/ba0a4df8c563536857dcbf7b4dbd0f2a15f57ace"
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{
"url": "https://git.kernel.org/stable/c/08bc6173fd611ad5a40f472bf5f15b92aea0fe40"
},
{
"url": "https://git.kernel.org/stable/c/770444611f047dbfd4517ec0bc1b179d40c2f346"
}
],
"title": "libceph: Use u32 for non-negative values in ceph_monmap_decode()",
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"cveId": "CVE-2026-43405",
"datePublished": "2026-05-08T14:21:45.581Z",
"dateReserved": "2026-05-01T14:12:56.007Z",
"dateUpdated": "2026-05-09T04:10:50.413Z",
"state": "PUBLISHED"
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"cve": "CVE-2026-43405",
"date": "2026-05-09",
"epss": "0.00024",
"percentile": "0.07036"
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}
}
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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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