CVE-2025-21764

HIGHPre-NVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2025-02-27. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
7.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.8Exploit: NoneExposed: 0

A fix is available — apply it.

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

ndisc: use RCU protection in ndisc_alloc_skb()

ndisc_alloc_skb() can be called without RTNL or RCU being held.

Add RCU protection to avoid possible UAF.

CVSS v3
7.8
EG Score
7.8(medium)
EG Risk
35(Track)
EG Risk 35/100SSVC: 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
Severity78% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
15.4%
KEV
Not listed

Published

February 27, 2025

Last Modified

July 14, 2026

Advisory Details (10)

Auto-updated Jul 14, 2026
Patch available.
generic Patch Available

[SECURITY] [DLA 4178-1] linux security update

https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
generic Patch Available

[SECURITY] [DLA 4102-1] linux-6.1 security update

https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html
generic

ndisc: use RCU protection in ndisc_alloc_skb() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/cd1065f92eb7ff21b9ba5308a86f33d1670bf926
generic

ndisc: use RCU protection in ndisc_alloc_skb() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c30893ef3d9cde8e7e8e4fd06b53d2c935bbccb1
generic

ndisc: use RCU protection in ndisc_alloc_skb() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/bbec88e4108e8d6fb468d3817fa652140a44ff28
generic

ndisc: use RCU protection in ndisc_alloc_skb() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b870256dd2a5648d5ed2f22316b3ac29a7e5ed63
generic

ndisc: use RCU protection in ndisc_alloc_skb() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/9e0ec817eb41a55327a46cd3ce331a9868d60304
generic

ndisc: use RCU protection in ndisc_alloc_skb() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/96fc896d0e5b37c12808df797397fb16f3080879
generic

ndisc: use RCU protection in ndisc_alloc_skb() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/628e6d18930bbd21f2d4562228afe27694f66da9
generic

ndisc: use RCU protection in ndisc_alloc_skb() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/3c2d705f5adf5d860aaef90cb4211c0fde2ba66d

Vendor Advisories for CVE-2025-21764(14)

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

Patch Availability(31)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-tools-kvm (5.4.0.1133.129) @ focal2026-05-21ubuntu
ubuntulinux-tools-ibm-edge (5.4.0.1092.97~18.04.1) @ bionic2026-05-21ubuntu
ubuntulinux-tools-azure-fips (5.4.0.1151.88) @ focal2026-05-21ubuntu
ubuntulinux-tools-nvidia-tegra-rt (5.15.0.1037.37) @ jammy2026-05-21ubuntu
ubuntulinux-virtual-hwe-18.04-edge (5.4.0.216.236~18.04.1) @ bionic2026-05-21ubuntu
ubuntulinux-tools-bluefield (5.4.0.1105.101) @ focal2026-05-21ubuntu
ubuntulinux-tools-oracle-edge (5.4.0.1144.154~18.04.1) @ bionic2026-05-21ubuntu
ubuntulinux-tools-aws (6.11.0-1014.15) @ oracular2026-05-21ubuntu
ubuntulinux-tools-ibm-lts-20.04 (5.4.0.1092.121) @ focal2026-05-21ubuntu
ubuntulinux-tools-aws-fips (5.15.0.1084.80) @ jammy2026-05-21ubuntu
ubuntulinux-tools-oracle-64k (6.11.0-1016.17) @ oracular2026-05-21ubuntu
ubuntulinux-tools-intel-iotg-edge (5.15.0.1079.85~20.04.1) @ focal2026-05-21ubuntu
ubuntulinux-tools-raspi2-hwe-18.04-edge (5.4.0.1129.160) @ focal2026-05-21ubuntu
ubuntulinux-tools-raspi-hwe-18.04-edge (5.4.0.1129.142~18.04.1) @ bionic2026-05-21ubuntu
ubuntulinux-tools-aws-lts-20.04 (5.4.0.1146.143) @ focal2026-05-21ubuntu
ubuntulinux-virtual-hwe-20.04-edge (5.15.0.142.152~20.04.1) @ focal2026-05-21ubuntu
ubuntulinux-tools-raspi-6.8 (6.8.0-1035.39) @ noble2026-05-21ubuntu
redhatkernel-0:4.18.0-477.100.1.el8_82025-07-02redhat
redhatkernel-rt-0:4.18.0-553.58.1.rt7.399.el8_102025-06-25redhat
redhatkernel-0:4.18.0-553.58.1.el8_102025-06-25redhat
redhatkernel-0:5.14.0-427.74.1.el9_42025-06-25redhat
redhatkernel-rt-0:5.14.0-284.121.1.rt14.406.el9_22025-06-24redhat
redhatkernel-rt-0:5.14.0-70.134.1.rt21.206.el9_02025-06-24redhat
redhatkernel-0:4.18.0-305.159.1.el8_42025-06-24redhat
redhatkernel-0:4.18.0-372.149.1.el8_62025-06-24redhat
redhatkernel-0:5.14.0-284.121.1.el9_22025-06-24redhat
redhatkernel-0:4.18.0-193.154.1.el8_22025-06-24redhat
redhatkernel-0:5.14.0-70.134.1.el9_02025-06-24redhat
redhatkernel-0:6.12.0-55.17.1.el10_02025-06-16redhat
redhatkernel-0:5.14.0-570.19.1.el9_62025-06-02redhat
linuxKernel @ 5.4.291—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

(12)

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 11× in last 7d / 47× 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. 2026-07-23 02:50 UTCEG score recompute
  2. 2026-07-22 14:07 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2025-21764?
CVE-2025-21764 is a high vulnerability published on February 27, 2025. In the Linux kernel, the following vulnerability has been resolved: ndisc: use RCU protection in ndiscallocskb() ndiscallocskb() can be called without RTNL or RCU being held. Add RCU protection to avoid possible UAF.
When was CVE-2025-21764 disclosed?
CVE-2025-21764 was first published in the National Vulnerability Database on February 27, 2025, 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-2025-21764 actively exploited?
CVE-2025-21764 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 15.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2025-21764?
CVE-2025-21764 has a CVSS v3.1 base score of 7.8 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2025-21764?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-21764, 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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