CVE-2025-21891

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2025-03-27. 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

A fix is available — apply it.

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

ipvlan: ensure network headers are in skb linear part

syzbot found that ipvlan_process_v6_outbound() was assuming the IPv6 network header isis present in skb->head [1]

Add the needed pskb_network_may_pull() calls for both IPv4 and IPv6 handlers.

[1] BUG: KMSAN: uninit-value in __ipv6_addr_type+0xa2/0x490 net/ipv6/addrconf_core.c:47 __ipv6_addr_type+0xa2/0x490 net/ipv6/addrconf_core.c:47 ipv6_addr_type include/net/ipv6.h:555 [inline] ip6_route_output_flags_noref net/ipv6/route.c:2616 [inline] ip6_route_output_flags+0x51/0x720 net/ipv6/route.c:2651 ip6_route_output include/net/ip6_route.h:93 [inline] ipvlan_route_v6_outbound+0x24e/0x520 drivers/net/ipvlan/ipvlan_core.c:476 ipvlan_process_v6_outbound drivers/net/ipvlan/ipvlan_core.c:491 [inline] ipvlan_process_outbound drivers/net/ipvlan/ipvlan_core.c:541 [inline] ipvlan_xmit_mode_l3 drivers/net/ipvlan/ipvlan_core.c:605 [inline] ipvlan_queue_xmit+0xd72/0x1780 drivers/net/ipvlan/ipvlan_core.c:671 ipvlan_start_xmit+0x5b/0x210 drivers/net/ipvlan/ipvlan_main.c:223 __netdev_start_xmit include/linux/netdevice.h:5150 [inline] netdev_start_xmit include/linux/netdevice.h:5159 [inline] xmit_one net/core/dev.c:3735 [inline] dev_hard_start_xmit+0x247/0xa20 net/core/dev.c:3751 sch_direct_xmit+0x399/0xd40 net/sched/sch_generic.c:343 qdisc_restart net/sched/sch_generic.c:408 [inline] __qdisc_run+0x14da/0x35d0 net/sched/sch_generic.c:416 qdisc_run+0x141/0x4d0 include/net/pkt_sched.h:127 net_tx_action+0x78b/0x940 net/core/dev.c:5484 handle_softirqs+0x1a0/0x7c0 kernel/softirq.c:561 __do_softirq+0x14/0x1a kernel/softirq.c:595 do_softirq+0x9a/0x100 kernel/softirq.c:462 __local_bh_enable_ip+0x9f/0xb0 kernel/softirq.c:389 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline] __dev_queue_xmit+0x2758/0x57d0 net/core/dev.c:4611 dev_queue_xmit include/linux/netdevice.h:3311 [inline] packet_xmit+0x9c/0x6c0 net/packet/af_packet.c:276 packet_snd net/packet/af_packet.c:3132 [inline] packet_sendmsg+0x93e0/0xa7e0 net/packet/af_packet.c:3164 sock_sendmsg_nosec net/socket.c:718 [inline]

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
25(Track)
EG Risk 25/100SSVC: 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%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
7.7%
KEV
Not listed

Published

March 27, 2025

Last Modified

November 3, 2025

References (6)

Vendor Advisories for CVE-2025-21891(1)

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

Patch Availability(18)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-virtual-hwe-24.04-edge (6.11.0-26.26) @ oracular2026-05-30ubuntu
ubuntulinux-tools-gcp-edge (6.8.0-1040.42~22.04.1) @ jammy2026-05-30ubuntu
ubuntulinux-tools-aws (6.11.0-1014.15) @ oracular2026-05-30ubuntu
ubuntulinux-tools-realtime-6.8.1 (6.8.1-1034.35) @ noble2026-05-30ubuntu
ubuntulinux-tools-oracle-64k (6.11.0-1016.17) @ oracular2026-05-30ubuntu
ubuntulinux-virtual-6.8 (6.8.0-84.84) @ noble2026-05-30ubuntu
ubuntulinux-tools-raspi-6.8 (6.8.0-1039.43) @ noble2026-05-30ubuntu
ubuntulinux-tools-ibm-edge (6.8.0-1037.37~22.04.1) @ jammy2026-05-30ubuntu
ubuntulinux-tools-realtime-hwe-22.04 (6.8.1-1034.35~22.04.1) @ jammy2026-05-30ubuntu
ubuntulinux-virtual-hwe-22.04-edge (6.8.0-84.84~22.04.1) @ jammy2026-05-30ubuntu
ubuntulinux-tools-nvidia-lowlatency-64k-6.8 (6.8.0-1039.42.1) @ noble2026-05-30ubuntu
ubuntulinux-tools-raspi-realtime-6.8 (6.8.0-2031.32) @ noble2026-05-30ubuntu
ubuntulinux-tools-azure-lts-24.04 (6.8.0-1038.44) @ noble2026-05-30ubuntu
ubuntulinux-tools-azure-nvidia-lts-24.04 (6.8.0-1025.27) @ noble2026-05-30ubuntu
ubuntulinux-virtual-hwe-22.04-edge (6.8.0-85.85~22.04.1) @ jammy2026-05-30ubuntu
ubuntulinux-tools-oracle-lts-24.04 (6.8.0-1037.38) @ noble2026-05-30ubuntu
ubuntulinux-tools-oracle-edge (6.8.0-1037.38~22.04.1) @ jammy2026-05-30ubuntu
linuxKernel @ 6.1.130—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.

Additional Vendor Advisories

(17)

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

Frequently asked(5)

What is CVE-2025-21891?
CVE-2025-21891 is a medium vulnerability published on March 27, 2025. In the Linux kernel, the following vulnerability has been resolved: ipvlan: ensure network headers are in skb linear part syzbot found that ipvlanprocessv6_outbound() was assuming the IPv6 network header isis present in skb->head [1] Add the needed pskbnetworkmay_pull() calls for both IPv4 and IPv6…
When was CVE-2025-21891 disclosed?
CVE-2025-21891 was first published in the National Vulnerability Database on March 27, 2025, with the most recent update on November 3, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-21891 actively exploited?
CVE-2025-21891 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 7.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2025-21891?
CVE-2025-21891 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2025-21891?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-21891, 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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