No exploitation reportedFix available

CVE-2025-21758

Q: Is CVE-2025-21758 actively exploited?

Active exploitation of CVE-2025-21758 has not been confirmed. Its EPSS score was 16.9% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2025-21758?

CVE-2025-21758 has a CVSS v3 base score of 5.5 (MEDIUM severity), with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

No exploitation reported by the sources we read.

Published2025-02-27
Fixed in6.13.4 · 6.12.16 · 6.6.79 · 6.1.129 · 5.15.179

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: add RCU protection to mld_newpack() mld_newpack() can be called without RTNL or RCU being held. Note that we no longer can use sock_alloc_send_skb() because ipv6.igmp_sk uses GFP_KERNEL allocations which can sleep. Instead use alloc_skb() and charge the net->ipv6.igmp_sk socket under RCU protection.

Timeline

dates in UTC

2025-02-2703:15CVE publishedNVD
2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2025-21758?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2025-21758?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Linux linux kernel

Branch	Affected	Fixed in	Source
6.13	≥ 6.13, < 6.13.4	6.13.4	NVD
6.x	≥ 6.7, < 6.12.16	6.12.16	NVD
6.x	≥ 6.2, < 6.6.79	6.6.79	NVD
6.1	≥ 5.16, < 6.1.129	6.1.129	NVD
5.15	≥ 2.6.26, < 5.15.179	5.15.179	NVD
6.14	= 6.14	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Linux linux kernel to 6.13.4 · 6.12.16 · 6.6.79 · 6.1.129 · 5.15.179

Advisories and patches

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CNACVSS 3.17.8read 2026-10-23
NVDCVSS 3.15.5read 2026-10-23
FIRST EPSSEPSS score16.9 %read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Published: 2025-02-27
Last Modified: 2026-10-15
NVD status: Modified

Frequently asked questions

What is CVE-2025-21758?

Is CVE-2025-21758 actively exploited?

Active exploitation of CVE-2025-21758 has not been confirmed. Its EPSS score was 16.9% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2025-21758?

CVE-2025-21758 has a CVSS v3 base score of 5.5 (MEDIUM severity), with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

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