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TI-2026-55806 Aliases CVE-2026-80793GHSA-vc8f-29mh-24xv

ipv4: reject undersized MTUs in ip_do_fragment()

Priority LOW 22Published · Updated

Key facts

Attack vector
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Privileges required
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User interaction
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Attack complexity
—
Impact type
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Confidentiality · integrity · availability
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Fix status
Partial Red Hat: 7 without a fix

No CVSS vector from any source. Fix status from CNA and Red Hat.

Summary

In the Linux kernel, the following vulnerability has been resolved: ipv4: reject undersized MTUs in ip_do_fragment() ip_do_fragment() subtracts the IPv4 header length from the effective MTU and passes the resulting payload MTU to ip_frag_next(). If the effective MTU is smaller than hlen + 8, ip_frag_next() rounds the fragment payload length down to zero. The fragmentation state then never makes forward progress: state->left, state->ptr and state->offset stay unchanged while ip_do_fragment() keeps allocating and transmitting header-only fragments until the softlockup detector fires. This is reproducible with a route installed using "mtu lock 20", but it is also reproducible without route MTU lock, for example by forwarding a packet to a device whose MTU is 20. Fix it in ip_do_fragment() by rejecting mtu < hlen + 8 with -EMSGSIZE, matching the existing IPv6 fragmentation check.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00195 9th percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.267, 5.15.218, 6.1.185 +6Red Hat: 7 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux2.6.12 and later5.10.267, 5.15.218, 6.1.185, 6.6.154, 6.12.106, 6.18.47, 7.1.11, 7.2.1, 7.3Patch availableCNA
  • Linux VendorLinux Affected 2.6.12 and later Fixed in 5.10.267, 5.15.218, 6.1.185, 6.6.154, 6.12.106, 6.18.47, 7.1.11, 7.2.1, 7.3 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*——Linux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions — — ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.10.267, 5.15.218, 6.1.185, 6.6.154, 6.12.106, 6.18.47, 7.1.11, 7.2.1, 7.3

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 8AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 4AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 5AffectedNo fix yet: Fix deferred

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-80793
  2. 2026-10-03 Alias added: GHSA-vc8f-29mh-24xv
  3. 2026-10-18 Affected versions changed · Red Hat
  4. 2026-10-18 CVSS score added · Red Hat
  5. 2026-10-19 Fix available: Linux/[email protected] · CNA
  6. 2026-11-06 Affected versions changed · Red Hat
  7. 2026-11-06 CISA SSVC decision points changed

References

Other 9

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2021-02452 Incorrect authorization in Ubuntu linux kernel KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
See all 21741 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences