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
Trending — 3 sources updated this week
5.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.5Exploit: 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:

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)
EPSS
2.2%
KEV
Not listed

Published

March 26, 2026

Last Modified

July 14, 2026

References (10)

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(1)

Vendor / EcosystemFixed in / PatchReleasedSource
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.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 52× 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 124 total refreshes for this CVE.

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

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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 2.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
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.

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