CVE-2026-45905

MEDIUMNVD 4.74.7—
EchelonGraph scoreMEDIUM confidence

Score 4.7 from GitHub Security Advisory published 2026-05-27. NVD baseline CVSS 4.7; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
4.7
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 4.7Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

In the Linux kernel, the following vulnerability has been resolved:

xfrm: fix ip_rt_bug race in icmp_route_lookup reverse path

icmp_route_lookup() performs multiple route lookups to find a suitable route for sending ICMP error messages, with special handling for XFRM (IPsec) policies.

The lookup sequence is:

  • First, lookup output route for ICMP reply (dst = original src)
  • Pass through xfrm_lookup() for policy check
  • If blocked (-EPERM) or dst is not local, enter "reverse path"
  • In reverse path, call xfrm_decode_session_reverse() to get fl4_dec
which reverses the original packet's flow (saddr<->daddr swapped)
  • If fl4_dec.saddr is local (we are the original destination), use
__ip_route_output_key() for output route lookup
  • If fl4_dec.saddr is NOT local (we are a forwarding node), use
ip_route_input() to simulate the reverse packet's input path
  • Finally, pass rt2 through xfrm_lookup() with XFRM_LOOKUP_ICMP flag

The bug occurs in step 6: ip_route_input() is called with fl4_dec.daddr (original packet's source) as destination. If this address becomes local between the initial check and ip_route_input() call (e.g., due to concurrent "ip addr add"), ip_route_input() returns a LOCAL route with dst.output set to ip_rt_bug.

This route is then used for ICMP output, causing dst_output() to call ip_rt_bug(), triggering a WARN_ON:

------------[ cut here ]------------ WARNING: net/ipv4/route.c:1275 at ip_rt_bug+0x21/0x30, CPU#1 Call Trace: ip_push_pending_frames+0x202/0x240 icmp_push_reply+0x30d/0x430 __icmp_send+0x1149/0x24f0 ip_options_compile+0xa2/0xd0 ip_rcv_finish_core+0x829/0x1950 ip_rcv+0x2d7/0x420 __netif_receive_skb_one_core+0x185/0x1f0 netif_receive_skb+0x90/0x450 tun_get_user+0x3413/0x3fb0 tun_chr_write_iter+0xe4/0x220 ...

Fix this by checking rt2->rt_type after ip_route_input(). If it's RTN_LOCAL, the route cannot be used for output, so treat it as an error.

The reproducer requires kernel modification to widen the race window, making it unsuitable as a selftest. It is available at:

https://gist.github.com/mrpre/eae853b72ac6a750f5d45d64ddac1e81

CVSS v3
4.7
EG Score
4.7(medium)
EG Risk
26(Track)
EG Risk 26/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity47% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
1.6%
KEV
Not listed

Published

May 27, 2026

Last Modified

June 24, 2026

Advisory Details (6)

Auto-updated Jun 24, 2026
No patch confirmed yet.
generic

xfrm: fix ip_rt_bug race in icmp_route_lookup reverse path - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b04061f89ffc6168e7ec3c71d0086ec3c3797228
generic

xfrm: fix ip_rt_bug race in icmp_route_lookup reverse path - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/9a95ec9144eeff1fc6fbcc21b677e322c6f1430b
generic

xfrm: fix ip_rt_bug race in icmp_route_lookup reverse path - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/81b84de32bb27ae1ae2eb9acf0420e9d0d14bf00
generic

xfrm: fix ip_rt_bug race in icmp_route_lookup reverse path - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/423ce12d10b426709489d6b84fdaa6d2f31c5652
generic

xfrm: fix ip_rt_bug race in icmp_route_lookup reverse path - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/2c1f59005da9dd4b07b26984fd719e36557dc57c
generic

xfrm: fix ip_rt_bug race in icmp_route_lookup reverse path - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/1c9ef28f643cce34a6a6c36c8f4d6d60a60db7e1

Vendor Advisories for CVE-2026-45905(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 33× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-25 14:18 UTCEPSS rescore
  2. 2026-07-24 14:17 UTCEPSS rescore
  3. 2026-07-23 14:18 UTCEPSS rescore
  4. 2026-07-23 03:16 UTCEG score recompute
  5. 2026-07-22 14:08 UTCEPSS rescore
  6. 2026-07-21 15:24 UTCEPSS rescore
  7. 2026-07-20 17:08 UTCEPSS rescore
  8. 2026-07-19 14:31 UTCEPSS rescore
  9. 2026-07-18 10:04 UTCEPSS rescore
  10. 2026-07-16 17:03 UTCEPSS rescore
  11. 2026-07-15 16:57 UTCEPSS rescore
  12. 2026-07-13 22:30 UTCEPSS rescore
  13. 2026-07-13 06:13 UTCEPSS rescore
  14. 2026-07-11 08:27 UTCEPSS rescore
  15. 2026-07-09 19:10 UTCEPSS rescore
  16. 2026-07-09 00:24 UTCGHSA enrichment
  17. 2026-07-08 15:16 UTCEPSS rescore
  18. 2026-07-07 13:46 UTCEPSS rescore
  19. 2026-07-06 16:27 UTCEPSS rescore
  20. 2026-07-06 02:23 UTCEPSS rescore
  21. 2026-07-05 02:30 UTCEPSS rescore
  22. 2026-07-04 06:31 UTCEPSS rescore
  23. 2026-07-01 15:07 UTCEPSS rescore
  24. 2026-07-01 11:36 UTCGHSA enrichment
  25. 2026-06-30 23:22 UTCEPSS rescore
Show 65 more
  1. 2026-06-29 14:30 UTCGHSA enrichment
  2. 2026-06-28 14:07 UTCEPSS rescore
  3. 2026-06-28 07:27 UTCGHSA enrichment
  4. 2026-06-28 04:56 UTCEPSS rescore
  5. 2026-06-28 04:56 UTCEPSS rescore
  6. 2026-06-27 06:34 UTCGHSA enrichment
  7. 2026-06-27 03:08 UTCEPSS rescore
  8. 2026-06-26 02:45 UTCGHSA enrichment
  9. 2026-06-25 13:49 UTCEPSS rescore
  10. 2026-06-25 01:44 UTCEG score recompute▲ 4.70
  11. 2026-06-25 01:44 UTCGHSA enrichment
  12. 2026-06-24 18:02 UTCNVD updateCVSS v3 → 4.7 · severity → MEDIUM
  13. 2026-06-24 14:05 UTCEPSS rescore
  14. 2026-06-23 21:33 UTCEPSS rescore
  15. 2026-06-23 21:33 UTCEPSS rescore
  16. 2026-06-22 14:25 UTCEPSS rescore
  17. 2026-06-22 14:25 UTCEPSS rescore
  18. 2026-06-21 14:56 UTCEPSS rescore
  19. 2026-06-21 14:56 UTCEPSS rescore
  20. 2026-06-21 01:59 UTCEPSS rescore
  21. 2026-06-21 01:59 UTCEPSS rescore
  22. 2026-06-19 19:26 UTCEPSS rescore
  23. 2026-06-19 19:26 UTCEPSS rescore
  24. 2026-06-18 17:52 UTCEPSS rescore
  25. 2026-06-18 17:52 UTCEPSS rescore
  26. 2026-06-17 23:37 UTCGHSA enrichment
  27. 2026-06-17 17:53 UTCEPSS rescore
  28. 2026-06-16 17:52 UTCEPSS rescore
  29. 2026-06-15 17:49 UTCEPSS rescore
  30. 2026-06-15 03:42 UTCGHSA enrichment
  31. 2026-06-13 23:00 UTCEPSS rescore
  32. 2026-06-12 23:12 UTCEPSS rescore
  33. 2026-06-12 23:12 UTCEPSS rescore
  34. 2026-06-12 08:05 UTCGHSA enrichment
  35. 2026-06-11 14:00 UTCEPSS rescore
  36. 2026-06-10 22:18 UTCEPSS rescore
  37. 2026-06-10 13:22 UTCEPSS rescore
  38. 2026-06-10 13:22 UTCEPSS rescore
  39. 2026-06-09 12:29 UTCGHSA enrichment
  40. 2026-06-08 14:17 UTCEPSS rescore
  41. 2026-06-08 14:17 UTCEPSS rescore
  42. 2026-06-07 15:25 UTCEPSS rescore
  43. 2026-06-07 15:25 UTCEPSS rescore
  44. 2026-06-06 16:53 UTCGHSA enrichment
  45. 2026-06-06 13:47 UTCEPSS rescore
  46. 2026-06-06 13:47 UTCEPSS rescore
  47. 2026-06-05 22:47 UTCEPSS rescore
  48. 2026-06-05 06:10 UTCEPSS rescore
  49. 2026-06-05 06:10 UTCEPSS rescore
  50. 2026-06-04 13:12 UTCEPSS rescore
  51. 2026-06-04 13:12 UTCEPSS rescore
  52. 2026-06-03 21:17 UTCGHSA enrichment
  53. 2026-06-02 20:13 UTCEPSS rescore
  54. 2026-06-01 13:52 UTCEPSS rescore
  55. 2026-06-01 13:52 UTCEPSS rescore
  56. 2026-06-01 01:41 UTCGHSA enrichment
  57. 2026-05-31 22:30 UTCEPSS rescore
  58. 2026-05-31 22:30 UTCEPSS rescore
  59. 2026-05-31 00:16 UTCEPSS rescore
  60. 2026-05-31 00:16 UTCEPSS rescore
  61. 2026-05-29 13:44 UTCEPSS rescore
  62. 2026-05-29 13:44 UTCEPSS rescore
  63. 2026-05-28 13:44 UTCEPSS rescore
  64. 2026-05-28 13:44 UTCEPSS rescore
  65. 2026-05-27 14:17 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-45905?
CVE-2026-45905 is a medium vulnerability published on May 27, 2026. In the Linux kernel, the following vulnerability has been resolved: xfrm: fix iprtbug race in icmproutelookup reverse path icmproutelookup() performs multiple route lookups to find a suitable route for sending ICMP error messages, with special handling for XFRM (IPsec) policies. The lookup sequence…
When was CVE-2026-45905 disclosed?
CVE-2026-45905 was first published in the National Vulnerability Database on May 27, 2026, with the most recent update on June 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-45905 actively exploited?
CVE-2026-45905 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-45905?
CVE-2026-45905 has a CVSS v3 base score of 4.7 (NVD).
How do I remediate CVE-2026-45905?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-45905, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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