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NVD / CVE Program· CNA Linux

CVE-2026-31411: net: atm: fix crash due to unvalidated vcc pointer in sigd_send()

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: 0.13% (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.
  • Fixed version: Linux Linux 1c8bda3df028d5e54134077dcd09f46ca8cfceb5, 21c303fec138c002f90ed33bce60e807d53072bb, 3e1a8b00095246a9a2b46b57f6d471c6d3c00ed2.

Low priority for now. Upgrade to Linux Linux 1c8bda3df028d5e54134077dcd09f46ca8cfceb5, 21c303fec138c002f90ed33bce60e807d53072bb, 3e1a8b00095246a9a2b46b57f6d471c6d3c00ed2 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: atm: fix crash due to unvalidated vcc pointer in sigd_send() Reproducer available at [1]. The ATM send path (sendmsg -> vcc_sendmsg -> sigd_send) reads the vcc pointer from msg->vcc and uses it directly without any validation. This pointer comes from userspace via sendmsg() and can be arbitrarily forged: int fd = socket(AF_ATMSVC, SOCK_DGRAM, 0); ioctl(fd, ATMSIGD_CTRL); // become ATM signaling daemon struct msghdr msg = { .msg_iov = &iov, ... }; *(unsigned long *)(buf + 4) = 0xdeadbeef; // fake vcc pointer sendmsg(fd, &msg, 0); // kernel dereferences 0xdeadbeef In normal operation, the kernel sends the vcc pointer to the signaling daemon via sigd_enq() when processing operations like connect(), bind(), or listen(). The daemon is expected to return the same pointer when responding. However, a malicious daemon can send arbitrary pointer values. Fix this by introducing find_get_vcc() which validates the pointer by searching through vcc_hash (similar to how sigd_close() iterates over all VCCs), and acquires a reference via sock_hold() if found. Since struct atm_vcc embeds struct sock as its first member, they share the same lifetime. Therefore using sock_hold/sock_put is sufficient to keep the vcc alive while it is being used. Note that there may be a race with sigd_close() which could mark the vcc with various flags (e.g., ATM_VF_RELEASED) after find_get_vcc() returns. However, sock_hold() guarantees the memory remains valid, so this race only affects the logical state, not memory safety. [1]: https://gist.github.com/mrpre/1ba5949c45529c511152e2f4c755b0f3

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Apr 8, 2026
Updated
Oct 15, 2026
EPSS
0.1% · 2th 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 · 0.1%

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  • A fix has been released

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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.

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 kernel2.6.12.1 and later · before 5.10.252
  • linux linux kernel5.11 and later · before 5.15.202
  • linux linux kernel5.16 and later · before 6.1.165
  • linux linux kernel6.2 and later · before 6.6.128
  • linux linux kernel6.7 and later · before 6.12.75
  • linux linux kernel6.13 and later · before 6.18.14
  • linux linux kernel6.19 and later · before 6.19.4
  • linux linux kernel2.6.12
  • linux linux kernel7.0

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 c96549d07dfdd51aadf0722cfb40711574424840affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 1c8bda3df028d5e54134077dcd09f46ca8cfceb5affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 3e1a8b00095246a9a2b46b57f6d471c6d3c00ed2affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before e3f80666c2739296c3b69a127300455c43aa1067affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 21c303fec138c002f90ed33bce60e807d53072bbaffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 69d3f9ee5489e6e8b66defcfa226e91d82393297affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 440c9a5fc477a8ee259d8bf669531250b8398651affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before ae88a5d2f29b69819dc7b04086734439d074a643affected · 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
AlmaLinux:9kernelbefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-64kbefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-64k-corebefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-64k-debugbefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-64k-debug-corebefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-64k-debug-develbefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-64k-debug-devel-matchedbefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-64k-debug-modulesbefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-64k-debug-modules-corebefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-64k-debug-modules-extrabefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-64k-develbefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-64k-devel-matchedbefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-64k-modulesbefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-64k-modules-corebefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-64k-modules-extrabefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-abi-stablelistsbefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-corebefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-cross-headersbefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-debugbefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-debug-corebefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-debug-develbefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-debug-devel-matchedbefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-debug-modulesbefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8
AlmaLinux:9kernel-debug-modules-corebefore 5.14.0-687.20.1.el9_85.14.0-687.20.1.el9_8

+96

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-2026-31408Apr 6, 2026 · Bluetooth: SCO: Fix use-after-free in sco_recv_frame() due to missing sock_hold
    35Monitor
  • ← EarlierCVE-2026-31410Apr 6, 2026 · ksmbd: use volume UUID in FS_OBJECT_ID_INFORMATION
    22Monitor
  • Later →CVE-2026-39860Apr 8, 2026 · Nix sandbox escape: file write via symlink at FOD `.tmp` copy destination
    33Monitor

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 Linux1c8bda3df028d5e54134077dcd09f46ca8cfceb5Vendor (CNA)
Linux Linux21c303fec138c002f90ed33bce60e807d53072bbVendor (CNA)
Linux Linux3e1a8b00095246a9a2b46b57f6d471c6d3c00ed2Vendor (CNA)
Linux Linux440c9a5fc477a8ee259d8bf669531250b8398651Vendor (CNA)
Linux Linux69d3f9ee5489e6e8b66defcfa226e91d82393297Vendor (CNA)
Linux Linuxae88a5d2f29b69819dc7b04086734439d074a643Vendor (CNA)
Linux Linuxc96549d07dfdd51aadf0722cfb40711574424840Vendor (CNA)
Linux Linuxe3f80666c2739296c3b69a127300455c43aa1067Vendor (CNA)
almalinux:kernel5.14.0-687.20.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k5.14.0-687.20.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-core5.14.0-687.20.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug5.14.0-687.20.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-core5.14.0-687.20.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel5.14.0-687.20.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched5.14.0-687.20.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules5.14.0-687.20.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-core5.14.0-687.20.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-extra5.14.0-687.20.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-devel5.14.0-687.20.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-devel-matched5.14.0-687.20.1.el9_8 · AlmaLinux:9Package registry (OSV)
debian:linux6.1.170-1 · Debian:12Package registry (OSV)
red hat:kernel-64k-debug-debuginfo0:5.14.0-687.20.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-devel0:5.14.0-687.20.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-devel-matched0:5.14.0-687.20.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-debuginfo0:5.14.0-687.20.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-devel0:5.14.0-687.20.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-64k-devel-matched0:5.14.0-687.20.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-debug-debuginfo0:5.14.0-687.20.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-debug-devel0:5.14.0-687.20.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)
red hat:kernel-debug-devel-matched0:5.14.0-687.20.1.el9_8 · Red Hat:enterprise_linux:9::appstreamPackage registry (OSV)

+3

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

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 (10 more)

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

All records