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NVD / CVE Program· CNA Linux

CVE-2026-74628: net/x25: fix use-after-free of the socket by its timers

Noroxi assessment

Priority: Monitor (action score 39/100)

  • 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: 0.50% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 1fc9f6d2c7c9fdb341bfe8ca449c990632299ea6, 2195424c3da2ef1829a63b807e3a900a90e57d85, 3c4919be5d910db4beebca420953858606fba7d8; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 1fc9f6d2c7c9fdb341bfe8ca449c990632299ea6, 2195424c3da2ef1829a63b807e3a900a90e57d85, 3c4919be5d910db4beebca420953858606fba7d8; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1 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: net/x25: fix use-after-free of the socket by its timers The x25 timers are armed with mod_timer() and cancelled with timer_delete(), so a pending timer holds no reference on the socket and a cancel does not wait for a callback already running on another CPU. x25_heartbeat_expiry() also rearms unconditionally, so it can reinstall sk->sk_timer after __x25_destroy_socket() has passed its cancel point. The following __sock_put() frees the socket while the timer is still queued, and the next expiry uses freed memory. KASAN reports a slab-use-after-free on the kmalloc-2k object freed by close(). timer_delete_sync() cannot be used here: x25_heartbeat_expiry() and x25_timer_expiry() both reach the cancels from inside the timer they would wait on, through __x25_destroy_socket() and x25_disconnect(). Arm the timers with sk_reset_timer() and cancel them with sk_stop_timer() so that an armed timer owns a reference, and release it in both expiry handlers. Rearm the heartbeat only while sk_hashed(sk) is still true, since __x25_destroy_socket() unlinks the socket before dropping it. Arm the deferred destroy timer the same way and drop its reference in x25_destroy_timer(). Reproduced on net with KASAN, with the heartbeat period shortened so the window recurs. With this patch the reproducer no longer triggers a report and /proc/net/x25 drains. Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>

CriticalCVSS 9.8 · v3.1—No exploit Fix available
Published
Aug 22, 2026
Updated
Oct 14, 2026
EPSS
0.5% · 43th percentile
CWE
—

Report tools

JSON

Action score

39

Monitor

Low priority for now.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CNA vs NVD score

NVD
—
CNA · Linux
9.8
NVD has not scored this yet; the score shown is the CNA’s.

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

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  • A fix has been released

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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.

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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.

—

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

    • 2.6.12affected
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before ba925a2e98ce967a0e71c5bcbcf5dbd3facaf0c8affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 6b79659590f0f82a9b8efd2ffd55ec6399ebfc33affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before fdd9ac50b9b61ef2b2d52c5156aff788be91454daffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 1fc9f6d2c7c9fdb341bfe8ca449c990632299ea6affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 3c4919be5d910db4beebca420953858606fba7d8affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 4bc522b33438fefc3272840ae5988771863a4f1faffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before e92c7e2b41d1528a830bc64c5e4e46dfa8133ddaaffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 2195424c3da2ef1829a63b807e3a900a90e57d85affected · git
    • before 2.6.12not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.187-16.1.187-1
Debian:12linux-6.12before 6.12.107-1~deb12u16.12.107-1~deb12u1
Debian:13linuxbefore 6.12.105-16.12.105-1
Debian:14linuxbefore 7.1.9-17.1.9-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-74626Aug 22, 2026 · NTB: ntb_netdev: Preserve RX queue depth on allocation failure
    30Monitor
  • ← EarlierCVE-2026-74627Aug 22, 2026 · net: devmem: prevent net-iov / page mixing
    31Monitor
  • Later →CVE-2026-74629Aug 22, 2026 · net/dibs: Correct freeing of dmb_clientid_arr
    35Monitor

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 Linux1fc9f6d2c7c9fdb341bfe8ca449c990632299ea6Vendor (CNA)
Linux Linux2195424c3da2ef1829a63b807e3a900a90e57d85Vendor (CNA)
Linux Linux3c4919be5d910db4beebca420953858606fba7d8Vendor (CNA)
Linux Linux4bc522b33438fefc3272840ae5988771863a4f1fVendor (CNA)
Linux Linux6b79659590f0f82a9b8efd2ffd55ec6399ebfc33Vendor (CNA)
Linux Linuxba925a2e98ce967a0e71c5bcbcf5dbd3facaf0c8Vendor (CNA)
Linux Linuxe92c7e2b41d1528a830bc64c5e4e46dfa8133ddaVendor (CNA)
Linux Linuxfdd9ac50b9b61ef2b2d52c5156aff788be91454dVendor (CNA)
azl3 kernel 6.6.152.1-1 on Azure Linux 3.06.6.157.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.187-1 · Debian:12Package registry (OSV)
debian:linux-6.126.12.107-1~deb12u1 · 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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-secondary

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 (7 more)

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

All records