9.8

CVE-2025-21954: netmem: prevent TX of unreadable skbs

Modified
AliasesUBUNTU-CVE-2025-21954DEBIAN-CVE-2025-21954
Published 01-04-2025Last modified 05-08-2026

Vulnerability summary

CVE-2025-21954 is a critical (CVSS 9.8) vulnerability in linux. EPSS estimates a 0.51% chance of exploitation in the next 30 days, higher than 43.2% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 9.8 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 1% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
9.8/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.51%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 1
RHSA-2025:20095

Timeline

  1. 01-04-2025
    PublishedVulnerability first disclosed.
  2. 05-08-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: netmem: prevent TX of unreadable skbs Currently on stable trees we have support for netmem/devmem RX but not TX. It is not safe to forward/redirect an RX unreadable netmem packet into the device's TX path, as the device may call dma-mapping APIs on dma addrs that should not be passed to it. Fix this by preventing the xmit of unreadable skbs. Tested by configuring tc redirect: sudo tc qdisc add dev eth1 ingress sudo tc filter add dev eth1 ingress protocol ip prio 1 flower ip_proto \ tcp src_ip 192.168.1.12 action mirred egress redirect dev eth1 Before, I see unreadable skbs in the driver's TX path passed to dma mapping APIs. After, I don't see unreadable skbs in the driver's TX path passed to dma mapping APIs.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.51%

Chance of exploitation in the next 30 days

Percentile

43%

Versus all other CVEs

30-day change

Increase +0.01 pp

From 0.50% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu77 products
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
  • linux-aws-5.13All versions (No fix recorded)
  • linux-aws-5.19All versions (No fix recorded)
Linux2 products
  • linux≥ 65249feb6b3df9e17bab5911ee56fa7b0971e231, < 454825019d2f0c59e5174ece9e713f45ad80beff | ≥ 65249feb6b3df9e17bab5911ee56fa7b0971e231, < 1c17c8ced25c5fbe424c7ad7ea11d33014a986b1 | ≥ 65249feb6b3df9e17bab5911ee56fa7b0971e231, < f3600c867c99a2cc8038680ecf211089c50e7971 | 6.12
  • linux_kernel≥ 6.12, < 6.12.20 | ≥ 6.13, < 6.13.8 | 6.14:rc1 | 6.14:rc2 | 6.14:rc3 | 6.14:rc4 | 6.14:rc5 | 6.14:rc6
Debian1 product
  • linux< 6.12.20-1

3 vendors · 80 products

References

7 links