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TI-2026-31678 Aliases CVE-2026-43501GHSA-fqx3-r8j8-73qq

ipv6: rpl: reserve mac_len headroom when recompressed SRH grows

Priority MEDIUM 50CWE-787Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 28 fixed, 1 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-787 and the CVSS impact.

Summary

In the Linux kernel, the following vulnerability has been resolved: ipv6: rpl: reserve mac_len headroom when recompressed SRH grows ipv6_rpl_srh_rcv() decompresses an RFC 6554 Source Routing Header, swaps the next segment into ipv6_hdr->daddr, recompresses, then pulls the old header and pushes the new one plus the IPv6 header back. The recompressed header can be larger than the received one when the swap reduces the common-prefix length the segments share with daddr (CmprI=0, CmprE>0, seg[0][0] != daddr[0] gives the maximum +8 bytes). pskb_expand_head() was gated on segments_left == 0, so on earlier segments the push consumed unchecked headroom. Once skb_push() leaves fewer than skb->mac_len bytes in front of data, skb_mac_header_rebuild()'s call to: skb_set_mac_header(skb, -skb->mac_len); will store (data - head) - mac_len into the u16 mac_header field, which wraps to ~65530, and the following memmove() writes mac_len bytes ~64KiB past skb->head. A single AF_INET6/SOCK_RAW/IPV6_HDRINCL packet over lo with a two segment type-3 SRH (CmprI=0, CmprE=15) reaches headroom 8 after one pass; KASAN reports a 14-byte OOB write in ipv6_rthdr_rcv. Fix this by expanding the head whenever the remaining room is less than the push size plus mac_len, and request that much extra so the rebuilt MAC header fits afterwards.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00732 54th percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.258, 5.15.209, 6.1.175 +5Red Hat: 7 advisoriesRed Hat: 28 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

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

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux5.7 and later5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.86, 6.18.27, 7.0.4, 7.1Patch availableCNA
  • Linux VendorLinux Affected 5.7 and later Fixed in 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.86, 6.18.27, 7.0.4, 7.1 Patch available CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*5.7 to before 5.10.258; 5.11 to before 5.15.209; 5.16 to before 6.1.175; 6.2 to before 6.6.140; 6.7 to before 6.12.86; 6.13 to before 6.18.27; 6.19 to before 7.0.4VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*7.1 rc1VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.7 to before 5.10.258; 5.11 to before 5.15.209; 5.16 to before 6.1.175; 6.2 to before 6.6.140; 6.7 to before 6.12.86; 6.13 to before 6.18.27; 6.19 to before 7.0.4 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* Versions 7.1 rc1 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.86, 6.18.27, 7.0.4, 7.1

Red Hat 7 advisories

  • RHSA-2026:34094 Released 2026-07-01 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat CodeReady Linux Builder EUS (v.9.6) kernel-tools-libs-devel-5.14.0-570.125.1.el9_6, libperf-5.14.0-570.125.1.el9_6
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) kernel-64k-debug-devel-5.14.0-570.125.1.el9_6, kernel-64k-debug-devel-matched-5.14.0-570.125.1.el9_6, kernel-64k-devel-5.14.0-570.125.1.el9_6 +12
    • Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel-5.14.0-570.125.1.el9_6, kernel-64k-5.14.0-570.125.1.el9_6, kernel-64k-core-5.14.0-570.125.1.el9_6 +28
    • Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt-5.14.0-570.125.1.el9_6, kernel-rt-64k-5.14.0-570.125.1.el9_6, kernel-rt-64k-core-5.14.0-570.125.1.el9_6 +21
    • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt-5.14.0-570.125.1.el9_6, kernel-rt-core-5.14.0-570.125.1.el9_6, kernel-rt-debug-5.14.0-570.125.1.el9_6 +11
  • RHSA-2026:34095 Released 2026-07-01 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream E4S (v.9.2) kernel-64k-debug-devel-5.14.0-284.178.1.el9_2, kernel-64k-debug-devel-matched-5.14.0-284.178.1.el9_2, kernel-64k-devel-5.14.0-284.178.1.el9_2 +10
    • Red Hat Enterprise Linux BaseOS E4S (v.9.2) bpftool-7.0.0-284.178.1.el9_2, kernel-5.14.0-284.178.1.el9_2, kernel-64k-5.14.0-284.178.1.el9_2 +29
  • RHSA-2026:33900 Released 2026-07-01 · Red Hat rating Important
    kernel-rt security, bug fix, and enhancement update
    • Red Hat Enterprise Linux Real Time E4S (v.9.2) kernel-rt-5.14.0-284.178.1.rt14.463.el9_2, kernel-rt-core-5.14.0-284.178.1.rt14.463.el9_2, kernel-rt-debug-5.14.0-284.178.1.rt14.463.el9_2 +9
    • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) kernel-rt-5.14.0-284.178.1.rt14.463.el9_2, kernel-rt-core-5.14.0-284.178.1.rt14.463.el9_2, kernel-rt-debug-5.14.0-284.178.1.rt14.463.el9_2 +11
Show 4 more Red Hat advisories
  • RHSA-2026:27731 Released 2026-06-22 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) kernel-64k-debug-devel-6.12.0-55.82.1.el10_0, kernel-64k-debug-devel-matched-6.12.0-55.82.1.el10_0, kernel-64k-devel-6.12.0-55.82.1.el10_0 +12
    • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel-6.12.0-55.82.1.el10_0, kernel-64k-6.12.0-55.82.1.el10_0, kernel-64k-core-6.12.0-55.82.1.el10_0 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) kernel-tools-libs-devel-6.12.0-55.82.1.el10_0, libperf-6.12.0-55.82.1.el10_0
    • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt-6.12.0-55.82.1.el10_0, kernel-rt-64k-6.12.0-55.82.1.el10_0, kernel-rt-64k-core-6.12.0-55.82.1.el10_0 +21
    • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt-6.12.0-55.82.1.el10_0, kernel-rt-core-6.12.0-55.82.1.el10_0, kernel-rt-debug-6.12.0-55.82.1.el10_0 +11
  • RHSA-2026:27713 Released 2026-06-22 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream E4S (v.9.4) kernel-64k-debug-devel-5.14.0-427.134.1.el9_4, kernel-64k-debug-devel-matched-5.14.0-427.134.1.el9_4, kernel-64k-devel-5.14.0-427.134.1.el9_4 +11
    • Red Hat Enterprise Linux BaseOS E4S (v.9.4) bpftool-7.3.0-427.134.1.el9_4, kernel-5.14.0-427.134.1.el9_4, kernel-64k-5.14.0-427.134.1.el9_4 +29
    • Red Hat Enterprise Linux Real Time E4S (v.9.4) kernel-rt-5.14.0-427.134.1.el9_4, kernel-rt-core-5.14.0-427.134.1.el9_4, kernel-rt-debug-5.14.0-427.134.1.el9_4 +9
    • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4) kernel-rt-5.14.0-427.134.1.el9_4, kernel-rt-core-5.14.0-427.134.1.el9_4, kernel-rt-debug-5.14.0-427.134.1.el9_4 +11
  • RHSA-2026:25217 Released 2026-06-11 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.15.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.15.1.el9_8, kernel-64k-devel-5.14.0-687.15.1.el9_8 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.15.1.el9_8, kernel-64k-5.14.0-687.15.1.el9_8, kernel-64k-core-5.14.0-687.15.1.el9_8 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.15.1.el9_8, libperf-5.14.0-687.15.1.el9_8
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.15.1.el9_8, kernel-rt-64k-5.14.0-687.15.1.el9_8, kernel-rt-64k-core-5.14.0-687.15.1.el9_8 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.15.1.el9_8, kernel-rt-core-5.14.0-687.15.1.el9_8, kernel-rt-debug-5.14.0-687.15.1.el9_8 +9
  • RHSA-2026:25191 Released 2026-06-11 · Red Hat rating Critical
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.22.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.22.1.el10_2, kernel-64k-devel-6.12.0-211.22.1.el10_2 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.22.1.el10_2, kernel-64k-6.12.0-211.22.1.el10_2, kernel-64k-core-6.12.0-211.22.1.el10_2 +29
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.22.1.el10_2, libperf-6.12.0-211.22.1.el10_2
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.22.1.el10_2, kernel-rt-64k-6.12.0-211.22.1.el10_2, kernel-rt-64k-core-6.12.0-211.22.1.el10_2 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.22.1.el10_2, kernel-rt-core-6.12.0-211.22.1.el10_2, kernel-rt-debug-6.12.0-211.22.1.el10_2 +9

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat CodeReady Linux Builder EUS (v.9.6)Fixed RHSA-2026:34094
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:25191
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:25217
Red Hat Enterprise Linux AppStream E4S (v.9.2)Fixed RHSA-2026:34095
Red Hat Enterprise Linux AppStream E4S (v.9.4)Fixed RHSA-2026:27713
Red Hat Enterprise Linux AppStream EUS (v. 10.0)Fixed RHSA-2026:27731
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:34094
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:25191
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:25217
Red Hat Enterprise Linux BaseOS E4S (v.9.2)Fixed RHSA-2026:34095
Red Hat Enterprise Linux BaseOS E4S (v.9.4)Fixed RHSA-2026:27713
Red Hat Enterprise Linux BaseOS EUS (v. 10.0)Fixed RHSA-2026:27731
Red Hat Enterprise Linux BaseOS EUS (v.9.6)Fixed RHSA-2026:34094
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:25191
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:25217
Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0)Fixed RHSA-2026:27731
Red Hat Enterprise Linux Real Time (v. 10)Fixed RHSA-2026:25191
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2026:25217
Red Hat Enterprise Linux Real Time E4S (v.9.2)Fixed RHSA-2026:33900
Red Hat Enterprise Linux Real Time E4S (v.9.4)Fixed RHSA-2026:27713
Red Hat Enterprise Linux Real Time EUS (v. 10.0)Fixed RHSA-2026:27731
Red Hat Enterprise Linux Real Time EUS (v.9.6)Fixed RHSA-2026:34094
Red Hat Enterprise Linux Real Time for NFV (v. 10)Fixed RHSA-2026:25191
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2026:25217
Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2)Fixed RHSA-2026:33900
Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4)Fixed RHSA-2026:27713
Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0)Fixed RHSA-2026:27731
Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6)Fixed RHSA-2026:34094
Not affected: 3 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-43501
  2. 2026-10-03 Alias added: GHSA-fqx3-r8j8-73qq
  3. 2026-10-16 CISA SSVC decision points changed
  4. 2026-10-19 Weakness changed · CISA ADP

References

Patch 8

  • 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-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
  • TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
See all 15278 →

Sources

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