7.8

CVE-2025-21759: ipv6: mcast: extend RCU protection in igmp6_send()

Modified
AliasesUBUNTU-CVE-2025-21759DEBIAN-CVE-2025-21759
Published 27-02-2025Last modified 03-10-2026

Vulnerability summary

CVE-2025-21759 is a high (CVSS 7.8) Use After Free vulnerability in linux. EPSS estimates a 7.80% chance of exploitation in the next 30 days, higher than 94.6% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 7.8, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
7.8/10
010
High · v3.1 (CVE.org)
EPSS score
7.80%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 32 · Related 20
RHSA-2025:10371RHSA-2025:10379RHSA-2025:10829RHSA-2025:10830RHSA-2025:11245RHSA-2025:12209

Timeline

  1. 27-02-2025
    PublishedVulnerability first disclosed.
  2. 03-10-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: extend RCU protection in igmp6_send() igmp6_send() can be called without RTNL or RCU being held. Extend RCU protection so that we can safely fetch the net pointer and avoid a potential UAF. 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.

CVSS metrics

5 scores · 4 sources · 2 versions

EPSS trend

Probability

7.80%

Chance of exploitation in the next 30 days

Percentile

95%

Versus all other CVEs

30-day change

No change 0.00 pp

From 7.80% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu138 products
  • linuxAll versions (No fix recorded) | < 6.8.0-78.78
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 6.8.0-1035.37
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551, < 638e8fe3563a82f298fe537a28d5342a97278cf1 | ≥ b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551, < 6901bbb169e3add6c037218d996790cef6b3d650 | ≥ b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551, < 7e0a818ecc4d62e7fb668ea02de0bfe8ba0b7dff | ≥ b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551, < 81b25a07ebf53f9ef4ca8f3d96a8ddb94561dd5a | ≥ b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551, < 0bf8e2f3768629d437a32cb824149e6e98254381 | ≥ b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551, < 8e92d6a413feaf968a33f0b439ecf27404407458 | ≥ b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551, < 087c1faa594fa07a66933d750c0b2610aa1a2946 | 2.6.26
  • linux_kernel≥ 2.6.26, < 6.6.79 | ≥ 6.7, < 6.12.16 | ≥ 6.13, < 6.13.4 | 6.14:rc1 | 6.14:rc2
Debian1 product
  • linuxAll versions (No fix recorded) | < 6.1.190-1 | < 6.12.16-1

3 vendors · 141 products

References

21 links
Show all 21 references