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TI-2026-45572 Aliases CVE-2026-64007GHSA-rf6c-225m-p2p4

netfilter: synproxy: refresh tcphdr after skb_ensure_writable

Priority MEDIUM 49CWE-416Published · 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: 29 fixed, 2 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.

Summary

In the Linux kernel, the following vulnerability has been resolved: netfilter: synproxy: refresh tcphdr after skb_ensure_writable synproxy_tstamp_adjust() rewrites the TCP timestamp option in place and then patches the TCP checksum via inet_proto_csum_replace4() on the caller-supplied tcphdr pointer. Both ipv4_synproxy_hook() and ipv6_synproxy_hook() obtain that pointer with skb_header_pointer() before calling in, so it may either alias skb->head directly or point at the caller's on-stack _tcph buffer. Between obtaining the pointer and using it, the function calls skb_ensure_writable(skb, optend), which on a cloned or non-linear skb invokes pskb_expand_head() and frees the old skb->head. After that point the cached th is stale: caller (ipv[46]_synproxy_hook) th = skb_header_pointer(skb, ..., &_tcph) synproxy_tstamp_adjust(skb, protoff, th, ...) skb_ensure_writable(skb, optend) pskb_expand_head() /* kfree(old skb->head) */ ... inet_proto_csum_replace4(&th->check, ...) /* writes into freed head, or into the caller's stack copy leaving the on-wire checksum stale */ The option bytes are written through skb->data and are fine; only the checksum update goes through th and so lands in the wrong place. The result is either a write into freed slab memory or a packet leaving with a checksum that does not match its payload. Fix by re-deriving th from skb->data + protoff immediately after skb_ensure_writable() succeeds, so the subsequent checksum update targets the linear, writable header.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00514 44th percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.259, 5.15.210, 6.1.176 +5Red Hat: 11 advisoriesRed Hat: 29 fixed, 2 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
LinuxLinux3.12 and later5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12, 7.1Patch availableCNA
  • Linux VendorLinux Affected 3.12 and later Fixed in 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12, 7.1 Patch available CNA

CPE configurations NVD · 6

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*3.12 to before 5.10.259; 5.11 to before 5.15.210; 5.16 to before 6.1.176; 6.2 to before 6.6.143; 6.7 to before 6.12.93; 6.13 to before 6.18.35; 6.19 to before 7.0.12VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*7.1 rc1VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*7.1 rc2VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*7.1 rc3VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*7.1 rc4VulnerableLinux
cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:*7.1 rc5VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 3.12 to before 5.10.259; 5.11 to before 5.15.210; 5.16 to before 6.1.176; 6.2 to before 6.6.143; 6.7 to before 6.12.93; 6.13 to before 6.18.35; 6.19 to before 7.0.12 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* Versions 7.1 rc1 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* Versions 7.1 rc2 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* Versions 7.1 rc3 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* Versions 7.1 rc4 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:* Versions 7.1 rc5 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12, 7.1

Red Hat 11 advisories

  • RHSA-2026:94558 Released 2026-11-03 · Red Hat rating Critical
    kernel-rt security, bug fix, and enhancement update
    • Red Hat Enterprise Linux Real Time E4S (v.9.2) kernel-rt-5.14.0-284.202.1.rt14.487.el9_2, kernel-rt-core-5.14.0-284.202.1.rt14.487.el9_2, kernel-rt-debug-5.14.0-284.202.1.rt14.487.el9_2 +9
    • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) kernel-rt-5.14.0-284.202.1.rt14.487.el9_2, kernel-rt-core-5.14.0-284.202.1.rt14.487.el9_2, kernel-rt-debug-5.14.0-284.202.1.rt14.487.el9_2 +11
  • RHSA-2026:94477 Released 2026-11-03 · Red Hat rating Critical
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream E4S (v.9.2) kernel-64k-debug-devel-5.14.0-284.202.1.el9_2, kernel-64k-debug-devel-matched-5.14.0-284.202.1.el9_2, kernel-64k-devel-5.14.0-284.202.1.el9_2 +10
    • Red Hat Enterprise Linux BaseOS E4S (v.9.2) bpftool-7.0.0-284.202.1.el9_2, kernel-5.14.0-284.202.1.el9_2, kernel-64k-5.14.0-284.202.1.el9_2 +29
  • RHSA-2026:81349 Released 2026-10-12 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux Server (v. 7 ELS) bpftool-3.10.0-1160.167.1.el7, kernel-3.10.0-1160.167.1.el7, kernel-abi-whitelists-3.10.0-1160.167.1.el7 +11
    • Red Hat Enterprise Linux Server Optional (v. 7 ELS) kernel-debug-devel-3.10.0-1160.167.1.el7, kernel-tools-libs-devel-3.10.0-1160.167.1.el7
Show 8 more Red Hat advisories
  • RHSA-2026:81371 Released 2026-10-12 · Red Hat rating Important
    kernel-rt security, bug fix, and enhancement update
    • Red Hat Enterprise Linux for Real Time (v. 7 ELS) kernel-rt-3.10.0-1160.167.1.rt56.1319.el7, kernel-rt-debug-3.10.0-1160.167.1.rt56.1319.el7, kernel-rt-debug-devel-3.10.0-1160.167.1.rt56.1319.el7 +4
  • RHSA-2026:77634 Released 2026-10-08 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) kernel-64k-debug-devel-6.12.0-55.109.1.el10_0, kernel-64k-debug-devel-matched-6.12.0-55.109.1.el10_0, kernel-64k-devel-6.12.0-55.109.1.el10_0 +12
    • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel-6.12.0-55.109.1.el10_0, kernel-64k-6.12.0-55.109.1.el10_0, kernel-64k-core-6.12.0-55.109.1.el10_0 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) kernel-tools-libs-devel-6.12.0-55.109.1.el10_0, libperf-6.12.0-55.109.1.el10_0
    • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt-6.12.0-55.109.1.el10_0, kernel-rt-64k-6.12.0-55.109.1.el10_0, kernel-rt-64k-core-6.12.0-55.109.1.el10_0 +21
    • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt-6.12.0-55.109.1.el10_0, kernel-rt-core-6.12.0-55.109.1.el10_0, kernel-rt-debug-6.12.0-55.109.1.el10_0 +11
  • RHSA-2026:77218 Released 2026-10-07 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.4) kernel-64k-debug-devel-5.14.0-427.154.1.el9_4, kernel-64k-debug-devel-matched-5.14.0-427.154.1.el9_4, kernel-64k-devel-5.14.0-427.154.1.el9_4 +11
    • Red Hat Enterprise Linux BaseOS E4S (v.9.4) bpftool-7.3.0-427.154.1.el9_4, kernel-5.14.0-427.154.1.el9_4, kernel-64k-5.14.0-427.154.1.el9_4 +29
    • Red Hat Enterprise Linux Real Time E4S (v.9.4) kernel-rt-5.14.0-427.154.1.el9_4, kernel-rt-core-5.14.0-427.154.1.el9_4, kernel-rt-debug-5.14.0-427.154.1.el9_4 +9
    • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4) kernel-rt-5.14.0-427.154.1.el9_4, kernel-rt-core-5.14.0-427.154.1.el9_4, kernel-rt-debug-5.14.0-427.154.1.el9_4 +11
  • RHSA-2026:77217 Released 2026-10-07 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux BaseOS AUS (v.8.4) bpftool-4.18.0-305.211.1.el8_4, kernel-4.18.0-305.211.1.el8_4, kernel-abi-stablelists-4.18.0-305.211.1.el8_4 +14
    • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) bpftool-4.18.0-305.211.1.el8_4, kernel-4.18.0-305.211.1.el8_4, kernel-abi-stablelists-4.18.0-305.211.1.el8_4 +19
  • RHSA-2026:77216 Released 2026-10-07 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux BaseOS AUS (v.8.6) bpftool-4.18.0-372.220.1.el8_6, kernel-4.18.0-372.220.1.el8_6, kernel-abi-stablelists-4.18.0-372.220.1.el8_6 +14
    • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) bpftool-4.18.0-372.220.1.el8_6, kernel-4.18.0-372.220.1.el8_6, kernel-abi-stablelists-4.18.0-372.220.1.el8_6 +19
  • RHSA-2026:66000 Released 2026-09-09 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.160.1.el8_10, kernel-4.18.0-553.160.1.el8_10, kernel-abi-stablelists-4.18.0-553.160.1.el8_10 +19
    • Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.160.1.el8_10
  • RHSA-2026:64770 Released 2026-09-08 · Red Hat rating Important
    kernel-rt security update
    • Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-553.160.1.rt7.501.el8_10, kernel-rt-core-4.18.0-553.160.1.rt7.501.el8_10, kernel-rt-debug-4.18.0-553.160.1.rt7.501.el8_10 +9
    • Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-553.160.1.rt7.501.el8_10, kernel-rt-core-4.18.0-553.160.1.rt7.501.el8_10, kernel-rt-debug-4.18.0-553.160.1.rt7.501.el8_10 +7
  • RHSA-2026:57252 Released 2026-08-20 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.41.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.41.1.el9_8, kernel-64k-devel-5.14.0-687.41.1.el9_8 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.41.1.el9_8, kernel-64k-5.14.0-687.41.1.el9_8, kernel-64k-core-5.14.0-687.41.1.el9_8 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.41.1.el9_8, libperf-5.14.0-687.41.1.el9_8
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.41.1.el9_8, kernel-rt-64k-5.14.0-687.41.1.el9_8, kernel-rt-64k-core-5.14.0-687.41.1.el9_8 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.41.1.el9_8, kernel-rt-core-5.14.0-687.41.1.el9_8, kernel-rt-debug-5.14.0-687.41.1.el9_8 +9

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:57252
Red Hat Enterprise Linux AppStream E4S (v.9.2)Fixed RHSA-2026:94477
Red Hat Enterprise Linux AppStream E4S (v.9.4)Fixed RHSA-2026:77218
Red Hat Enterprise Linux AppStream EUS (v. 10.0)Fixed RHSA-2026:77634
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2026:66000
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:57252
Red Hat Enterprise Linux BaseOS AUS (v.8.4)Fixed RHSA-2026:77217
Red Hat Enterprise Linux BaseOS AUS (v.8.6)Fixed RHSA-2026:77216
Red Hat Enterprise Linux BaseOS E4S (v.9.2)Fixed RHSA-2026:94477
Red Hat Enterprise Linux BaseOS E4S (v.9.4)Fixed RHSA-2026:77218
Red Hat Enterprise Linux BaseOS EUS (v. 10.0)Fixed RHSA-2026:77634
Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)Fixed RHSA-2026:77217
Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6)Fixed RHSA-2026:77216
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2026:66000
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:57252
Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0)Fixed RHSA-2026:77634
Red Hat Enterprise Linux NFV (v. 8)Fixed RHSA-2026:64770
Red Hat Enterprise Linux RT (v. 8)Fixed RHSA-2026:64770
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2026:57252
Red Hat Enterprise Linux Real Time E4S (v.9.2)Fixed RHSA-2026:94558
Red Hat Enterprise Linux Real Time E4S (v.9.4)Fixed RHSA-2026:77218
Red Hat Enterprise Linux Real Time EUS (v. 10.0)Fixed RHSA-2026:77634
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2026:57252
Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2)Fixed RHSA-2026:94558
Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4)Fixed RHSA-2026:77218
Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0)Fixed RHSA-2026:77634
Red Hat Enterprise Linux Server (v. 7 ELS)Fixed RHSA-2026:81349
Red Hat Enterprise Linux Server Optional (v. 7 ELS)Fixed RHSA-2026:81349
Red Hat Enterprise Linux for Real Time (v. 7 ELS)Fixed RHSA-2026:81371
Not affected: 1 product
  • Red Hat Enterprise Linux 6

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-64007
  2. 2026-10-03 Alias added: GHSA-rf6c-225m-p2p4
  3. 2026-10-07 Fix available: RHSA-2026:77216 · Red Hat
  4. 2026-10-07 Fix available: Red Hat Enterprise Linux BaseOS AUS (v.8.6), Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) · Red Hat
  5. 2026-10-07 Fix available: RHSA-2026:77218 · Red Hat
  6. 2026-10-07 Fix available: RHSA-2026:77217 · Red Hat
  7. 2026-10-07 Fix available: Red Hat Enterprise Linux AppStream E4S (v.9.4), Red Hat Enterprise Linux BaseOS AUS (v.8.4), Red Hat Enterprise Linux BaseOS E4S (v.9.4) +3 · Red Hat
  8. 2026-10-08 Fix available: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux BaseOS EUS (v. 10.0), Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) +2 · Red Hat
  9. 2026-10-09 Fix available: RHSA-2026:77634 · Red Hat
  10. 2026-10-12 Fix available: RHSA-2026:81371 · Red Hat
  11. 2026-10-13 Fix available: RHSA-2026:81349 · Red Hat
  12. 2026-10-13 Fix available: Red Hat Enterprise Linux Server (v. 7 ELS), Red Hat Enterprise Linux Server Optional (v. 7 ELS), Red Hat Enterprise Linux for Real Time (v. 7 ELS) · Red Hat
  13. 2026-10-13 Weakness changed · NVD
  14. 2026-10-16 CISA SSVC decision points changed
  15. 2026-10-19 Weakness changed · CISA ADP
  16. 2026-11-03 Fix available: RHSA-2026:94477 · Red Hat
  17. 2026-11-03 Fix available: RHSA-2026:94558 · Red Hat
  18. 2026-11-03 Fix available: Red Hat Enterprise Linux AppStream E4S (v.9.2), Red Hat Enterprise Linux BaseOS E4S (v.9.2), Red Hat Enterprise Linux Real Time E4S (v.9.2) +1 · Red Hat

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