Skip to content
Noroxi
NVD / CVE Program· CNA Linux

CVE-2026-22991: libceph: make free_choose_arg_map() resilient to partial allocation

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.46% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Linux Linux 8081faaf089db5280c3be820948469f7c58ef8dd, 851241d3f78a5505224dc21c03d8692f530256b4, 9b3730dabcf3764bfe3ff07caf55e641a0b45234; cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.0 5.15.200.1-1.
  • Severity is disputed: the assigning authority (CNA) scores it 7.5, NVD 5.5.

Low priority for now. Upgrade to Linux Linux 8081faaf089db5280c3be820948469f7c58ef8dd, 851241d3f78a5505224dc21c03d8692f530256b4, 9b3730dabcf3764bfe3ff07caf55e641a0b45234; cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.0 5.15.200.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: libceph: make free_choose_arg_map() resilient to partial allocation free_choose_arg_map() may dereference a NULL pointer if its caller fails after a partial allocation. For example, in decode_choose_args(), if allocation of arg_map->args fails, execution jumps to the fail label and free_choose_arg_map() is called. Since arg_map->size is updated to a non-zero value before memory allocation, free_choose_arg_map() will iterate over arg_map->args and dereference a NULL pointer. To prevent this potential NULL pointer dereference and make free_choose_arg_map() more resilient, add checks for pointers before iterating.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jan 23, 2026
Updated
Oct 19, 2026
EPSS
0.4% · 40th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
5.5
CNA · Linux
7.5
2.0 point gap

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-22991

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

Running WordPress? Scan your site free with WP Lens

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for linux records

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel4.13 and later · before 5.10.248
  • linux linux kernel5.11 and later · before 5.15.198
  • linux linux kernel5.16 and later · before 6.1.161
  • linux linux kernel6.2 and later · before 6.6.121
  • linux linux kernel6.7 and later · before 6.12.66
  • linux linux kernel6.13 and later · before 6.18.6
  • linux linux kernel6.19

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 4.13affected
    • 5cf9c4a9959b6273675310d14a834ef14fbca37c and later · before 9b3730dabcf3764bfe3ff07caf55e641a0b45234affected · git
    • 5cf9c4a9959b6273675310d14a834ef14fbca37c and later · before 851241d3f78a5505224dc21c03d8692f530256b4affected · git
    • 5cf9c4a9959b6273675310d14a834ef14fbca37c and later · before ec1850f663da64842614c86b20fe734be070c2baaffected · git
    • 5cf9c4a9959b6273675310d14a834ef14fbca37c and later · before 8081faaf089db5280c3be820948469f7c58ef8ddaffected · git
    • 5cf9c4a9959b6273675310d14a834ef14fbca37c and later · before c4c2152a858c0ce4d2bff6ca8c1d5b0ef9f2cbdfaffected · git
    • 5cf9c4a9959b6273675310d14a834ef14fbca37c and later · before f21c3fdb96833aac2f533506899fe38c19cf49d5affected · git
    • 5cf9c4a9959b6273675310d14a834ef14fbca37c and later · before e3fe30e57649c551757a02e1cad073c47e1e075eaffected · git
    • before 4.13not affected · semver
    • 5.10.248 and later · up to and including 5.10.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.162-16.1.162-1
Debian:13linuxbefore 6.12.69-16.12.69-1
Debian:14linuxbefore 6.18.8-16.18.8-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-22989Jan 23, 2026 · nfsd: check that server is running in unlock_filesystem
    22Monitor
  • ← EarlierCVE-2026-22990Jan 23, 2026 · libceph: replace overzealous BUG_ON in osdmap_apply_incremental()
    22Monitor
  • Later →CVE-2026-22992Jan 23, 2026 · libceph: return the handler error from mon_handle_auth_done()
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux8081faaf089db5280c3be820948469f7c58ef8ddVendor (CNA)
Linux Linux851241d3f78a5505224dc21c03d8692f530256b4Vendor (CNA)
Linux Linux9b3730dabcf3764bfe3ff07caf55e641a0b45234Vendor (CNA)
Linux Linuxc4c2152a858c0ce4d2bff6ca8c1d5b0ef9f2cbdfVendor (CNA)
Linux Linuxe3fe30e57649c551757a02e1cad073c47e1e075eVendor (CNA)
Linux Linuxec1850f663da64842614c86b20fe734be070c2baVendor (CNA)
Linux Linuxf21c3fdb96833aac2f533506899fe38c19cf49d5Vendor (CNA)
cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.05.15.200.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.162-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-476 · NULL Pointer Dereference

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records