Vulnerability in Linux kernel
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-2025-21988 has been found in Linux kernel.
Attackers can target a specific entry point like prev_donated over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 9.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2025-21988" on the vendor's site.
CVE-2025-21988 (Linux kernel) — CVSS v3 9.8
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: prev_donated
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 (unclassified) exists in Linux kernel. Attackers reach the vulnerable code path via prev_donated without authentication.
Check the vendor advisory for the affected versions of Linux kernel. Attack surface: prev_donated.
Severity: Critical (CVSS 9.8/10). Successful exploitation can lead to full system takeover.
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
-
1
Identify exposureidentify
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。
-
2
Post-deployment verificationverify
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
| Ecosystem | Package | Affected | Fixed |
|---|---|---|---|
| Linux | Kernel |
≥ 6.12.0, < 6.12.20 ≥ 6.13.0, < 6.13.8 |
6.12.20 6.13.8 |
Fix status by distribution
Fixed packages published by each distribution for this CVE
- BellSoft Alpaquita BELL-CVE-2025-21988 linux-lts Fixed in: 6.12.41-r0
- Debian DEBIAN-CVE-2025-21988 linux Fixed in: 6.12.20-1
- Ubuntu UBUNTU-CVE-2025-21988 linux-hwe-edge
Original description The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
fs/netfs/read_collect: add to next->prev_donated
If multiple subrequests donate data to the same "next" request
(depending on the subrequest completion order), each of them would
overwrite the prev_donated field, causing data corruption and a
BUG() crash ("Can't donate prior to front").
Source: NIST National Vulnerability Database NVD
References
- advisory github.com
- advisory nvd.nist.gov
- package git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org