Categories
CVE-2025-21719 high CVSS 7.1

Out-of-Bounds Read in Linux kernel (CVE-2025-21719)

Summary

Vulnerability in Linux kernel (CVE-2025-21719). Confidential information can be exposed externally.

Original description

The description as published by the source.

In the Linux kernel, the following vulnerability has been resolved:

ipmr: do not call mr_mfc_uses_dev() for unres entries

syzbot found that calling mr_mfc_uses_dev() for unres entries
would crash [1], because c->mfc_un.res.minvif / c->mfc_un.res.maxvif
alias to "struct sk_buff_head unresolved", which contain two pointers.

This code never worked, lets remove it.

[1]
Unable to handle kernel paging request at virtual address ffff5fff2d536613
KASAN: maybe wild-memory-access in range [0xfffefff96a9b3098-0xfffefff96a9b309f]
Modules linked in:
CPU: 1 UID: 0 PID: 7321 Comm: syz.0.16 Not tainted 6.13.0-rc7-syzkaller-g1950a0af2d55 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : mr_mfc_uses_dev net/ipv4/ipmr_base.c:290 [inline]
pc : mr_table_dump+0x5a4/0x8b0 net/ipv4/ipmr_base.c:334
lr : mr_mfc_uses_dev net/ipv4/ipmr_base.c:289 [inline]
lr : mr_table_dump+0x694/0x8b0 net/ipv4/ipmr_base.c:334
Call trace:
mr_mfc_uses_dev net/ipv4/ipmr_base.c:290 [inline] (P)
mr_table_dump+0x5a4/0x8b0 net/ipv4/ipmr_base.c:334 (P)
mr_rtm_dumproute+0x254/0x454 net/ipv4/ipmr_base.c:382
ipmr_rtm_dumproute+0x248/0x4b4 net/ipv4/ipmr.c:2648
rtnl_dump_all+0x2e4/0x4e8 net/core/rtnetlink.c:4327
rtnl_dumpit+0x98/0x1d0 net/core/rtnetlink.c:6791
netlink_dump+0x4f0/0xbc0 net/netlink/af_netlink.c:2317
netlink_recvmsg+0x56c/0xe64 net/netlink/af_netlink.c:1973
sock_recvmsg_nosec net/so…

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-2025-21719 has been found in Linux kernel.
Confidential information can be exposed externally. CVSS score: 7.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2025-21719" on the vendor's site.

CVE-2025-21719 (Linux kernel) — CWE-125 / CVSS v3 7.1
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.

❓ What is the problem

Out-of-bounds read (CWE-125) exists in Linux kernel.

📍 Affected scope

Check the vendor advisory for the affected versions of Linux kernel.

🔥 Severity

Severity: High (CVSS 7.1/10). Confidential information can be exposed externally.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

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. 1
    Identify 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。

  2. 2
    Post-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

Linux Kernel
[{"type":"ECOSYSTEM","events":[{"introduced":"4.20.0"},{"fixed":"5.4.291"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.5.0"},{"fixed":"5.10.235"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.179"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.129"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.76"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.13"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.13.2"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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