CVE-2025-21758 in the critical feed json
ipv6: mcast: add RCU protection to mld_newpack()
published 2025-02-27 20 mo ago modified 2026-10-15 25 d ago also EUVD-2025-5151
- cvss
- 7.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 16.9%
- EPSS 16.9% chance of exploitation in 30 days, percentile 97%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- Linux Linux 5.15.179, 6.1.129, 6.6.79, 6.12.16, 6.13.4, 6.14
- linux Debian 12 6.1.129-1
- linux Debian 14, Debian 13 6.12.16-1
debian advisories DEBIAN-CVE-2025-21758
- linux Ubuntu 22.04 LTS 5.15.0-140.150
- linux Ubuntu 24.04 LTS 6.8.0-78.78
- linux-aws Ubuntu 22.04 LTS 5.15.0-1084.91
- linux-aws Ubuntu 24.04 LTS 6.8.0-1035.37
- linux-gcp Ubuntu 22.04 LTS 5.15.0-1083.92
- linux-gcp Ubuntu 24.04 LTS 6.8.0-1036.38
- linux-gke Ubuntu 22.04 LTS 5.15.0-1081.87
- linux-gke Ubuntu 24.04 LTS 6.8.0-1032.36
ubuntu advisories UBUNTU-CVE-2025-21758
Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0
- kernel-rt Real Time Module 15 SP7 6.4.0-150700.7.3.1
- kernel-syms-rt Real Time Module 15 SP7 6.4.0-150700.7.3.1
- kernel-rt_debug Real Time Module 15 SP7 6.4.0-150700.7.3.1
- kernel-source-rt Real Time Module 15 SP7 6.4.0-150700.7.3.1
- kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.20.3.1
- kernel-syms-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.20.3.1
- kernel-source-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.20.3.1
- kernel-rt Real Time Module 15 SP6, openSUSE Leap 15.6 6.4.0-150600.10.39.1
suse advisories SUSE-SU-2025:01972-1SUSE-SU-2025:01967-1SUSE-SU-2025:01964-1SUSE-SU-2025:01951-1SUSE-SU-2025:01919-1SUSE-SU-2025:01707-1
- git.kernel.org/stable/c/29fa42197f26a97cde29fa8c40beddf44ea5c8f3 commit
- git.kernel.org/stable/c/e8af3632a7f2da83e27b083f787bced1faba00b1 commit
- git.kernel.org/stable/c/1b91c597b0214b1b462eb627ec02658c944623f2 commit
- git.kernel.org/stable/c/25195f9d5ffcc8079ad743a50c0409dbdc48d98a commit
- git.kernel.org/stable/c/d60d493b0e65647e0335e6a7c4547abcea7df8e9 commit
- git.kernel.org/stable/c/a527750d877fd334de87eef81f1cb5f0f0ca3373 commit
Vendor advisories
What the vendors themselves say about their products: affected, fixed or not affected, and what to do.
red hat product security vex CVE-2025-21758 updated cvss 5.5
kernel: ipv6: mcast: add RCU protection to mld_newpack()
-
Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 moreaffected: no fix planned “Out of support scope”
-
Red Hat Enterprise Linux 10 kernelaffected: no fix planned “Will not fix”
-
Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +82 morenot affected: vulnerable code not present
Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf
cisa ICSA-26-295-11 updated cvss 7.8
Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP
-
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.7 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.7 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.7 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.7 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.7affected: mitigation, no fix available
Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf
cisa ICSA-26-295-16 updated cvss 7.8
Siemens SIMATIC S7-1500 TM MFP
-
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystemaffected: mitigation, no fix available
Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf
cisa ICSA-26-209-04 updated cvss 5.5
Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP
-
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.6 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.6 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.6 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.6 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.6affected: mitigation, no fix available
Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf
cisa ICSA-25-162-05 updated cvss 5.5
Siemens SIMATIC S7-1500 CPU family
-
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.5 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.5 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.5affected: mitigation, no fix available
Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf
Exploit prediction
16.93% chance of exploitation in the next 30 days, higher than 97% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVD | 3.1 | 5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
Affected products
- Linux Linux
- Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
- Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
- Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
- Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
Classification
- Technology feeds
References
-
git.kernel.org
/stable/c/29fa42197f26a97cde29fa8c40beddf44ea5c8f3
patch
-
git.kernel.org
/stable/c/e8af3632a7f2da83e27b083f787bced1faba00b1
patch
-
git.kernel.org
/stable/c/1b91c597b0214b1b462eb627ec02658c944623f2
patch
-
git.kernel.org
/stable/c/25195f9d5ffcc8079ad743a50c0409dbdc48d98a
patch
-
git.kernel.org
/stable/c/d60d493b0e65647e0335e6a7c4547abcea7df8e9
patch
-
git.kernel.org
/stable/c/a527750d877fd334de87eef81f1cb5f0f0ca3373
patch
- lists.debian.org /debian-lts-announce/2025/03/msg00028.html
- cert-portal.siemens.com /productcert/html/ssa-082556.html
- cert-portal.siemens.com /productcert/html/ssa-019113.html
- cert-portal.siemens.com /productcert/html/ssa-457936.html
- cert-portal.siemens.com /productcert/html/ssa-784472.html
Sources
- CVE List CVE-2025-21758
- NVD CVE-2025-21758
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.