CVE-2025-21719 | ipmr: do not call mr_mfc_uses_dev() for unres entries

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/socket.c:1033 [inline] sock_recvmsg net/socket.c:1055 [inline] sock_read_iter+0x2d8/0x40c net/socket.c:1125 new_sync_read fs/read_write.c:484 [inline] vfs_read+0x740/0x970 fs/read_write.c:565 ksys_read+0x15c/0x26c fs/read_write.c:708

Published: 2025-02-27 Last update: 2026-05-12 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Conclusion & alert: CVE-2025-21719 is rated Low Risk (31.8/100): CVSS High severity, with low exploitation likelihood (EPSS 0.03%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-21719

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-11-21 0.05% 0.03% -0.02%
2 2025-11-18 0.03% 0.05% +0.02%
3 2025-10-24 0.03%

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-21719

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.1 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
1.8 5.2 [email protected]

Weakness enumeration for CVE-2025-21719

GitHub Security Advisory for CVE-2025-21719

GHSA-cvf5-p5mj-6r49 · Severity: high — In the Linux kernel, the following vulnerability has been resolved: ipmr: do not call...

OS Trackers for CVE-2025-21719

vendor priority summary link
debian not yet assigned CVE-2025-21719 not yet assigned priority: Debian including 2 source packages (linux, linux-6.1), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6. https://security-tracker.debian.org/tracker/CVE-2025-21719
redhat low https://access.redhat.com/security/cve/CVE-2025-21719
suse medium CVE-2025-21719 severity moderate: SUSE including 417 source package names (2.1.3-6.11:kernel-default-6.4.0-28.1, 2.1.3-6.12:kernel-default-base-6.4.0-28.1.21.6, …), 724 product×package rows across 127 product lines (Container suse/sl-micro/6.0/base-os-container, Container suse/sl-micro/6.0/kvm-os-container, … (127 product lines)): Fixed 362, Known Affected 231, Known Not Affected 131. https://www.suse.com/security/cve/CVE-2025-21719/
ubuntu medium CVE-2025-21719 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1551 status rows across 10 suites (bionic, focal, jammy, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1145, released 190, ignored 148, not-affected 67, needed 1. https://ubuntu.com/security/CVE-2025-21719

Affected software / configurations for CVE-2025-21719

Vendor Product Version Raw CPE
linux linux_kernel >= 4.20, < 5.4.291 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.5, < 5.10.235 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.11, < 5.15.179 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.16, < 6.1.129 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.2, < 6.6.76 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.7, < 6.12.13 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.13, < 6.13.2 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

References for CVE-2025-21719

URL Tags
https://git.kernel.org/stable/c/15a901361ec3fb1c393f91880e1cbf24ec0a88bd Patch
https://git.kernel.org/stable/c/26bb7d991f04eeef47dfad23e533834995c26f7a Patch
https://git.kernel.org/stable/c/53df27fd38f84bd3cd6b004eb4ff3c4903114f1d Patch
https://git.kernel.org/stable/c/547ef7e8cbb98f966c8719a3e15d4e078aaa9b47 Patch
https://git.kernel.org/stable/c/57177c5f47a8da852f8d76cf6945cf803f8bb9e5 Patch
https://git.kernel.org/stable/c/71a0fcb68c0a5f3ec912b540cd5d72148e6ee5f1 Patch
https://git.kernel.org/stable/c/a099834a51ccf9bbba3de86a251b3433539abfde Patch
https://git.kernel.org/stable/c/b379b3162ff55a70464c6a934ae9bf0497478a62 Patch
https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html
https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
https://cert-portal.siemens.com/productcert/html/ssa-265688.html
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