CVE-2026-23398

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-03-26. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 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:

icmp: fix NULL pointer dereference in icmp_tag_validation()

icmp_tag_validation() unconditionally dereferences the result of rcu_dereference(inet_protos[proto]) without checking for NULL. The inet_protos[] array is sparse -- only about 15 of 256 protocol numbers have registered handlers. When ip_no_pmtu_disc is set to 3 (hardened PMTU mode) and the kernel receives an ICMP Fragmentation Needed error with a quoted inner IP header containing an unregistered protocol number, the NULL dereference causes a kernel panic in softirq context.

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] RIP: 0010:icmp_unreach (net/ipv4/icmp.c:1085 net/ipv4/icmp.c:1143) Call Trace: icmp_rcv (net/ipv4/icmp.c:1527) ip_protocol_deliver_rcu (net/ipv4/ip_input.c:207) ip_local_deliver_finish (net/ipv4/ip_input.c:242) ip_local_deliver (net/ipv4/ip_input.c:262) ip_rcv (net/ipv4/ip_input.c:573) __netif_receive_skb_one_core (net/core/dev.c:6164) process_backlog (net/core/dev.c:6628) handle_softirqs (kernel/softirq.c:561)

Add a NULL check before accessing icmp_strict_tag_validation. If the protocol has no registered handler, return false since it cannot perform strict tag validation.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: 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
Severity55% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
2%
KEV
Not listed

Published

March 26, 2026

Last Modified

July 14, 2026

Advisory Details (10)

Auto-updated Jul 19, 2026
⚠️ Active exploitation confirmed. No patch confirmed yet.
generic🔴 Active Exploitation

SSA-082556

https://cert-portal.siemens.com/productcert/html/ssa-082556.html
generic

SSA-019113

https://cert-portal.siemens.com/productcert/html/ssa-019113.html
generic

icmp: fix NULL pointer dereference in icmp_tag_validation() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/d938dd5a0ad780c891ea3bc94cae7405f11e618a
generic

icmp: fix NULL pointer dereference in icmp_tag_validation() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/d783fa413c702ff0f8f8bea63f862e28eeaf39e3
generic

icmp: fix NULL pointer dereference in icmp_tag_validation() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b61529c357f1ee4d64836eb142a542d2e7ad67ce
generic

icmp: fix NULL pointer dereference in icmp_tag_validation() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/9647e99d2a617c355d2b378be0ff6d0e848fd579
generic

icmp: fix NULL pointer dereference in icmp_tag_validation() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/614aefe56af8e13331e50220c936fc0689cf5675
generic

icmp: fix NULL pointer dereference in icmp_tag_validation() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/571d9d7b650f02d1e38c01128817868bceac9edd
generic

icmp: fix NULL pointer dereference in icmp_tag_validation() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/1f9f2c6d4b2a613b7756fc5679c5116ba2ca0161
generic

icmp: fix NULL pointer dereference in icmp_tag_validation() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/1e4e2f5e48cec0cccaea9815fb9486c084ba41e2

Vendor Advisories for CVE-2026-23398(2)

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

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 5.10.253—osv
linuxKernel @ 6.1.167—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(5 across 4 ecosystems)
Debian:11(2)
PackageVulnerable rangeFixed inDependents
linux5.10.103-1 ... 5.10.92-2 (53 versions)5.10.257-1—
linux-6.16.1.106-3~deb11u1 ... 6.1.164-1~deb11u1 (16 versions)6.1.170-1~deb11u1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 6.1.99-1 (48 versions)6.1.170-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.38-1 ... 6.12.85-1~bpo12+1 (17 versions)6.12.85-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 6.19~rc8-1~exp1 (119 versions)6.19.10-1—

Weakness Classification(1)

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

Additional Vendor Advisories

(24)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 7× in last 7d / 46× 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.

Showing the most recent 100 of 201 total refreshes for this CVE.

  1. 2026-09-04 05:06 UTCEPSS rescore
  2. 2026-09-02 14:11 UTCEPSS rescore
  3. 2026-09-02 13:57 UTCOSV refresh
  4. 2026-09-01 13:53 UTCEPSS rescore
  5. 2026-09-01 04:39 UTCEPSS rescore
  6. 2026-08-30 19:17 UTCEPSS rescore
  7. 2026-08-30 01:22 UTCEPSS rescore
  8. 2026-08-28 21:41 UTCEPSS rescore
  9. 2026-08-27 14:25 UTCEPSS rescore
  10. 2026-08-25 13:48 UTCEPSS rescore
  11. 2026-08-21 23:49 UTCEPSS rescore
  12. 2026-08-20 22:55 UTCEPSS rescore
  13. 2026-08-19 17:03 UTCEPSS rescore
  14. 2026-08-18 13:48 UTCEPSS rescore
  15. 2026-08-17 13:47 UTCEPSS rescore
  16. 2026-08-16 14:56 UTCEPSS rescore
  17. 2026-08-16 10:10 UTCEG score recompute
  18. 2026-08-16 10:10 UTCVendor advisory
  19. 2026-08-16 10:10 UTCGHSA enrichment
  20. 2026-08-16 02:14 UTCEPSS rescore
  21. 2026-08-15 01:30 UTCEPSS rescore
  22. 2026-08-14 06:28 UTCEG score recompute
  23. 2026-08-14 06:28 UTCVendor advisory
  24. 2026-08-14 06:28 UTCGHSA enrichment
  25. 2026-08-13 22:00 UTCEPSS rescore
Show 75 more
  1. 2026-08-12 20:45 UTCEG score recompute
  2. 2026-08-12 20:45 UTCVendor advisory
  3. 2026-08-12 20:45 UTCGHSA enrichment
  4. 2026-08-12 13:50 UTCEPSS rescore
  5. 2026-08-11 13:42 UTCEPSS rescore
  6. 2026-08-11 04:10 UTCEG score recompute
  7. 2026-08-11 04:10 UTCVendor advisory
  8. 2026-08-11 04:10 UTCGHSA enrichment
  9. 2026-08-11 00:00 UTCEPSS rescore
  10. 2026-08-10 05:06 UTCEG score recompute
  11. 2026-08-10 05:06 UTCVendor advisory
  12. 2026-08-10 05:06 UTCGHSA enrichment
  13. 2026-08-09 13:46 UTCEPSS rescore
  14. 2026-08-09 06:01 UTCEG score recompute
  15. 2026-08-09 06:01 UTCVendor advisory
  16. 2026-08-09 06:01 UTCGHSA enrichment
  17. 2026-08-08 16:37 UTCEPSS rescore
  18. 2026-08-07 16:25 UTCEG score recompute
  19. 2026-08-07 16:25 UTCVendor advisory
  20. 2026-08-07 16:25 UTCGHSA enrichment
  21. 2026-08-06 13:46 UTCEPSS rescore
  22. 2026-08-06 00:54 UTCEG score recompute
  23. 2026-08-06 00:54 UTCVendor advisory
  24. 2026-08-06 00:54 UTCGHSA enrichment
  25. 2026-08-05 19:17 UTCEPSS rescore
  26. 2026-08-04 15:10 UTCEPSS rescore
  27. 2026-08-04 10:38 UTCEPSS rescore
  28. 2026-08-03 23:19 UTCEG score recompute
  29. 2026-08-03 23:19 UTCVendor advisory
  30. 2026-08-03 23:19 UTCGHSA enrichment
  31. 2026-08-03 10:35 UTCEPSS rescore
  32. 2026-08-02 15:25 UTCEG score recompute
  33. 2026-08-02 15:25 UTCVendor advisory
  34. 2026-08-02 15:25 UTCGHSA enrichment
  35. 2026-08-02 02:26 UTCEPSS rescore
  36. 2026-08-01 04:15 UTCEPSS rescore
  37. 2026-07-30 01:30 UTCEPSS rescore
  38. 2026-07-27 14:13 UTCEPSS rescore
  39. 2026-07-26 14:54 UTCEPSS rescore
  40. 2026-07-26 14:54 UTCEPSS rescore
  41. 2026-07-25 14:17 UTCEPSS rescore
  42. 2026-07-25 14:17 UTCEPSS rescore
  43. 2026-07-24 14:17 UTCEPSS rescore
  44. 2026-07-23 14:18 UTCEPSS rescore
  45. 2026-07-23 14:18 UTCEPSS rescore
  46. 2026-07-23 03:07 UTCEG score recompute
  47. 2026-07-22 14:08 UTCEPSS rescore
  48. 2026-07-21 15:24 UTCEPSS rescore
  49. 2026-07-21 15:24 UTCEPSS rescore
  50. 2026-07-20 17:08 UTCEPSS rescore
  51. 2026-07-19 14:31 UTCEPSS rescore
  52. 2026-07-19 14:31 UTCEPSS rescore
  53. 2026-07-19 02:29 UTCEPSS rescore
  54. 2026-07-19 02:28 UTCEPSS rescore
  55. 2026-07-17 05:24 UTCOSV refresh
  56. 2026-07-16 17:03 UTCEPSS rescore
  57. 2026-07-16 17:03 UTCEPSS rescore
  58. 2026-07-15 16:57 UTCEPSS rescore
  59. 2026-07-15 16:57 UTCEPSS rescore
  60. 2026-07-15 02:00 UTCEPSS rescore
  61. 2026-07-15 02:00 UTCEPSS rescore
  62. 2026-07-14 13:19 UTCNVD updateCVSS v3 → 5.5 · severity → MEDIUM
  63. 2026-07-14 13:11 UTCMITRE cvelistV5
  64. 2026-07-13 22:30 UTCEPSS rescore
  65. 2026-07-13 06:13 UTCEPSS rescore
  66. 2026-07-13 06:13 UTCEPSS rescore
  67. 2026-07-12 05:46 UTCEPSS rescore
  68. 2026-07-12 05:46 UTCEPSS rescore
  69. 2026-07-11 08:27 UTCEPSS rescore
  70. 2026-07-09 19:10 UTCEPSS rescore
  71. 2026-07-08 15:15 UTCEPSS rescore
  72. 2026-07-08 15:15 UTCEPSS rescore
  73. 2026-07-07 13:46 UTCEPSS rescore
  74. 2026-07-06 16:27 UTCEPSS rescore
  75. 2026-07-06 16:27 UTCEPSS rescore

Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-23398?
CVE-2026-23398 is a medium vulnerability published on March 26, 2026. In the Linux kernel, the following vulnerability has been resolved: icmp: fix NULL pointer dereference in icmptagvalidation() icmptagvalidation() unconditionally dereferences the result of rcudereference(inetprotos[proto]) without checking for NULL. The inet_protos[] array is sparse -- only about…
When was CVE-2026-23398 disclosed?
CVE-2026-23398 was first published in the National Vulnerability Database on March 26, 2026, with the most recent update on July 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-23398 actively exploited?
CVE-2026-23398 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 97.5% of all scored CVEs.
What is the CVSS score of CVE-2026-23398?
CVE-2026-23398 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-23398?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-23398, 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.

Dependency Blast Radius

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