Vulnerability in Linux kernel (CVE-2025-21787)
Summary
Vulnerability in Linux kernel (CVE-2025-21787). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
team: better TEAM_OPTION_TYPE_STRING validation
syzbot reported following splat [1]
Make sure user-provided data contains one nul byte.
[1]
BUG: KMSAN: uninit-value in string_nocheck lib/vsprintf.c:633 [inline]
BUG: KMSAN: uninit-value in string+0x3ec/0x5f0 lib/vsprintf.c:714
string_nocheck lib/vsprintf.c:633 [inline]
string+0x3ec/0x5f0 lib/vsprintf.c:714
vsnprintf+0xa5d/0x1960 lib/vsprintf.c:2843
__request_module+0x252/0x9f0 kernel/module/kmod.c:149
team_mode_get drivers/net/team/team_core.c:480 [inline]
team_change_mode drivers/net/team/team_core.c:607 [inline]
team_mode_option_set+0x437/0x970 drivers/net/team/team_core.c:1401
team_option_set drivers/net/team/team_core.c:375 [inline]
team_nl_options_set_doit+0x1339/0x1f90 drivers/net/team/team_core.c:2662
genl_family_rcv_msg_doit net/netlink/genetlink.c:1115 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0x1214/0x12c0 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x375/0x650 net/netlink/af_netlink.c:2543
genl_rcv+0x40/0x60 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline]
netlink_unicast+0xf52/0x1260 net/netlink/af_netlink.c:1348
netlink_sendmsg+0x10da/0x11e0 net/netlink/af_netlink.c:1892
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg+0x30f/0x380 net/socket.c:733
____sys_sendmsg+0x877/0xb60 net/socket.c:2573
___sys_sendmsg+0x…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2025-21787 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure. CVSS score: 5.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2025-21787" on the vendor's site.
CVE-2025-21787 (Linux kernel) — CWE-908 / CVSS v3 5.5
Attack vector: local / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-908) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: Medium (CVSS 5.5/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- BellSoft Alpaquita BELL-CVE-2025-21787 linux-lts Fixed in: 6.1.130-r0
- Debian DEBIAN-CVE-2025-21787 linux Fixed in: 5.10.237-1
- Ubuntu UBUNTU-CVE-2025-21787 linux
References
- advisory nvd.nist.gov
- advisory github.com
- package git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web lists.debian.org
- web lists.debian.org
- web cert-portal.siemens.com
- web github.com
- web cert-portal.siemens.com