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TI-2026-47898 Aliases CVE-2026-68118GHSA-wr69-pfwc-72wx

tcp: challenge ACK for non-exact RST in SYN-RECEIVED

Priority MEDIUM 42CWE-20Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · Low · High
Fix status
Partial Red Hat: 7 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.

Summary

In the Linux kernel, the following vulnerability has been resolved: tcp: challenge ACK for non-exact RST in SYN-RECEIVED The SYN-RECEIVED request-socket path in tcp_check_req() accepts an in-window RST without requiring SEG.SEQ to exactly match RCV.NXT. A non-exact RST therefore removes the request instead of eliciting a challenge ACK. RFC 9293 section 3.10.7.4 applies the RFC 5961 reset check in SYN-RECEIVED: an exact RST resets the connection, while a non-exact in-window RST must trigger a challenge ACK and be dropped. Apply that check before the ACK-field validation, following the RFC sequence-number, RST, then ACK processing order. Factor the per-netns challenge ACK quota out of tcp_send_challenge_ack() so request sockets can share it. Use the request socket's send_ack() callback and its own out-of-window ACK timestamp to send and rate-limit the response.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00405 34th percentileScored 2026-11-07
Fix Partial Linux (Linux): 3.1, 3.3, 3.5 +6Red Hat: 7 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
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
LinuxLinux3.0.58 to before 3.1; 3.2.37 to before 3.3; 3.4.25 to before 3.53.1, 3.3, 3.5Patch availableCNA
LinuxLinux3.6 and later6.1.191, 6.6.153, 6.12.105, 6.18.42, 7.1.6, 7.2Patch availableCNA
  • Linux VendorLinux Affected 3.0.58 to before 3.1; 3.2.37 to before 3.3; 3.4.25 to before 3.5 Fixed in 3.1, 3.3, 3.5 Patch available CNA
  • Linux VendorLinux Affected 3.6 and later Fixed in 6.1.191, 6.6.153, 6.12.105, 6.18.42, 7.1.6, 7.2 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 3.1, 3.3, 3.5
  • Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.153, 6.12.105, 6.18.42, 7.1.6, 7.2

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 7AffectedNo fix yet
Red Hat Enterprise Linux 8AffectedNo fix yet
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat Enterprise Linux for NVIDIA 26AffectedNo fix planned: Out of support scope
Red Hat OpenShift Container Platform 4AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 5AffectedNo fix yet: Fix deferred
Not affected: 2 products
  • Red Hat Enterprise Linux 6
  • Red Hat OpenShift Container Platform 4

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-68118
  2. 2026-10-03 Alias added: GHSA-wr69-pfwc-72wx
  3. 2026-10-16 CISA SSVC decision points changed
  4. 2026-10-16 Priority changed: LOW → MEDIUM
  5. 2026-10-20 Weakness changed · CISA ADP
  6. 2026-10-27 CVSS score changed · Red Hat
  7. 2026-10-30 Affected versions changed · Red Hat
  8. 2026-10-30 Fix available: Linux/[email protected], Linux/Linux@c5dc463cc60eb26079b19607c9dbda76491dad05 · CNA
  9. 2026-10-30 1 new reference · CNA
  10. 2026-11-06 Affected versions changed · Red Hat

References

Other 6

  • 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