CVE-2026-31517

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-04-22. 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:

xfrm: iptfs: fix skb_put() panic on non-linear skb during reassembly

In iptfs_reassem_cont(), IP-TFS attempts to append data to the new inner packet 'newskb' that is being reassembled. First a zero-copy approach is tried if it succeeds then newskb becomes non-linear.

When a subsequent fragment in the same datagram does not meet the fast-path conditions, a memory copy is performed. It calls skb_put() to append the data and as newskb is non-linear it triggers SKB_LINEAR_ASSERT check.

Oops: invalid opcode: 0000 [#1] SMP NOPTI [...] RIP: 0010:skb_put+0x3c/0x40 [...] Call Trace: iptfs_reassem_cont+0x1ab/0x5e0 [xfrm_iptfs] iptfs_input_ordered+0x2af/0x380 [xfrm_iptfs] iptfs_input+0x122/0x3e0 [xfrm_iptfs] xfrm_input+0x91e/0x1a50 xfrm4_esp_rcv+0x3a/0x110 ip_protocol_deliver_rcu+0x1d7/0x1f0 ip_local_deliver_finish+0xbe/0x1e0 __netif_receive_skb_core.constprop.0+0xb56/0x1120 __netif_receive_skb_list_core+0x133/0x2b0 netif_receive_skb_list_internal+0x1ff/0x3f0 napi_complete_done+0x81/0x220 virtnet_poll+0x9d6/0x116e [virtio_net] __napi_poll.constprop.0+0x2b/0x270 net_rx_action+0x162/0x360 handle_softirqs+0xdc/0x510 __irq_exit_rcu+0xe7/0x110 irq_exit_rcu+0xe/0x20 common_interrupt+0x85/0xa0

Fix this by checking if the skb is non-linear. If it is, linearize it by calling skb_linearize(). As the initial allocation of newskb originally reserved enough tailroom for the entire reassembled packet we do not need to check if we have enough tailroom or extend it.

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

April 22, 2026

Last Modified

April 28, 2026

References (3)

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 6.18.21—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 12× in last 7d / 45× 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 127 total refreshes for this CVE.

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

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-31517?
CVE-2026-31517 is a medium vulnerability published on April 22, 2026. In the Linux kernel, the following vulnerability has been resolved: xfrm: iptfs: fix skb_put() panic on non-linear skb during reassembly In iptfsreassemcont(), IP-TFS attempts to append data to the new inner packet 'newskb' that is being reassembled. First a zero-copy approach is tried if it…
When was CVE-2026-31517 disclosed?
CVE-2026-31517 was first published in the National Vulnerability Database on April 22, 2026, with the most recent update on April 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-31517 actively exploited?
CVE-2026-31517 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 97.8% of all scored CVEs.
What is the CVSS score of CVE-2026-31517?
CVE-2026-31517 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-31517?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-31517, 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

Explore the affected products and dependency analysis for CVE-2026-31517

Explore →

Is Your Infrastructure Affected by CVE-2026-31517?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs