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CVE-2026-80784· NVD / CVE Program· CNA Linux

mptcp: pm: fix memory leak from alloc-during-teardown race

Noroxi assessment

Priority: Monitor (action score 0/100)

  • 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: 0.17% (FIRST EPSS).
  • Fixed version: Linux Linux 6c290915a03fc8228b473641025cf762b256dbd2, 9fe5eebb664ecdba88f3fde18062d94b1d1c465f, b2a0b55bf613bd3e81ed26a847b0f6b8e6b7f804; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1.

Low priority for now. Upgrade to Linux Linux 6c290915a03fc8228b473641025cf762b256dbd2, 9fe5eebb664ecdba88f3fde18062d94b1d1c465f, b2a0b55bf613bd3e81ed26a847b0f6b8e6b7f804; 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: mptcp: pm: fix memory leak from alloc-during-teardown race mptcp_pm_destroy() empties msk->pm.anno_list and msk->pm.userspace_pm_local_addr_list under msk->pm.lock during socket teardown, dropping the lock between the two. A concurrent userspace PM genl ANNOUNCE on the same msk holds a sock reference via mptcp_token_get_sock() and, in mptcp_pm_nl_announce_doit(), calls mptcp_userspace_pm_append_new_local_addr() and mptcp_pm_announced_alloc(). Both take msk->pm.lock briefly to add to their respective lists. Because the genl handler holds a sock reference, mptcp_pm_destroy() may run on the same msk via mptcp_disconnect(), which invokes mptcp_destroy_common() without dropping the sock refcount, before the handler completes. If the lock acquisitions interleave such that mptcp_pm_destroy() empties a list first, the later alloc adds its entry to a list head that nothing else iterates for this msk, and the entry leaks. kmemleak reports both mptcp_pm_add_addr objects (from mptcp_pm_announced_alloc()) and mptcp_pm_addr_entry objects (from mptcp_userspace_pm_append_new_local_addr()) under sustained concurrent ANNOUNCE + close load against the userspace PM. Add an MPTCP_PM_DESTROYING bit in msk->pm.status, set by mptcp_pm_destroy() under pm.lock before the lists are emptied and checked under pm.lock by the alloc paths. Either the alloc takes pm.lock first, in which case its entry is on the list when mptcp_pm_destroy() frees it; or mptcp_pm_destroy() takes pm.lock first, in which case the later alloc observes the bit and refuses. Found by an MPTCP protocol-flow harness extending BRF (arXiv:2305.08782).

—No exploit Fix available
Published
Sep 4, 2026
Updated
Sep 4, 2026
EPSS
0.1% · 6th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

What does it mean in your environment?

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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

    • 5.19affected
    • 9ab4807c84a4aacfc9b4f79cc81254035e0ec361 and later · before f48341830e4202db3fe884b819b2db6740f0537daffected · git
    • 9ab4807c84a4aacfc9b4f79cc81254035e0ec361 and later · before bb32e9a6a9a9f99eeda16c4efe443400f3e43892affected · git
    • 9ab4807c84a4aacfc9b4f79cc81254035e0ec361 and later · before b2a0b55bf613bd3e81ed26a847b0f6b8e6b7f804affected · git
    • 9ab4807c84a4aacfc9b4f79cc81254035e0ec361 and later · before 9fe5eebb664ecdba88f3fde18062d94b1d1c465faffected · git
    • 9ab4807c84a4aacfc9b4f79cc81254035e0ec361 and later · before 6c290915a03fc8228b473641025cf762b256dbd2affected · git
    • 9ab4807c84a4aacfc9b4f79cc81254035e0ec361 and later · before efc33b5102ff859bacd390a5f30112d8e0c084c0affected · git
    • before 5.19not affected · semver
    • 6.1.187 and later · up to and including 6.1.*not affected · semver
    • 6.6.154 and later · up to and including 6.6.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.187-16.1.187-1
Debian:12linux-6.12before 6.12.107-1~deb12u16.12.107-1~deb12u1
Debian:13linuxbefore 6.12.107-16.12.107-1
Debian:14linuxbefore 7.1.12-17.1.12-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

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Published before and after this one in the same product

  • ← EarlierCVE-2026-80754Sep 3, 2026 · Input: synaptics-rmi4 - fix F55 transmitter electrode count typo
    31Monitor
  • ← EarlierCVE-2026-80776Sep 4, 2026 · futex: Fix race in futex_pivot_pending() during private hash resize
    0Monitor
  • Later →CVE-2026-80785Sep 4, 2026 · fbdev: serialize mode sysfs access with lock_fb_info()
    0Monitor

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 Linux6c290915a03fc8228b473641025cf762b256dbd2Vendor (CNA)
Linux Linux9fe5eebb664ecdba88f3fde18062d94b1d1c465fVendor (CNA)
Linux Linuxb2a0b55bf613bd3e81ed26a847b0f6b8e6b7f804Vendor (CNA)
Linux Linuxbb32e9a6a9a9f99eeda16c4efe443400f3e43892Vendor (CNA)
Linux Linuxefc33b5102ff859bacd390a5f30112d8e0c084c0Vendor (CNA)
Linux Linuxf48341830e4202db3fe884b819b2db6740f0537dVendor (CNA)
azl3 kernel 6.6.150.1-1 on Azure Linux 3.0—Microsoft (MSRC)
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).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

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✗ → ✓

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References

Show all references (5 more)

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

All records