9.8

CVE-2021-47013: net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send

Modified
AliasesUBUNTU-CVE-2021-47013DEBIAN-CVE-2021-47013
Published 28-02-2024Last modified 05-08-2026

Vulnerability summary

CVE-2021-47013 is a critical (CVSS 9.8) Use After Free vulnerability in linux. EPSS estimates a 0.79% chance of exploitation in the next 30 days, higher than 56.3% 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
0.79%
0%100%
Low · 0.00 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 12 · Related 8
RHSA-2024:3462RHSA-2024:3618RHSA-2024:3627RHSA-2024:3810SUSE-SU-2024:0856-1SUSE-SU-2024:0857-1

Timeline

  1. 28-02-2024
    PublishedVulnerability first disclosed.
  2. 05-08-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send In emac_mac_tx_buf_send, it calls emac_tx_fill_tpd(..,skb,..). If some error happens in emac_tx_fill_tpd(), the skb will be freed via dev_kfree_skb(skb) in error branch of emac_tx_fill_tpd(). But the freed skb is still used via skb->len by netdev_sent_queue(,skb->len). As i observed that emac_tx_fill_tpd() haven't modified the value of skb->len, thus my patch assigns skb->len to 'len' before the possible free and use 'len' instead of skb->len later.

CVSS metrics

5 scores · 4 sources · 2 versions

EPSS trend

Probability

0.79%

Chance of exploitation in the next 30 days

Percentile

56%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.79% 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.

Ubuntu85 products
  • linux< 4.15.0-151.157 | < 5.4.0-77.86
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 4.15.0-1109.116 | < 5.4.0-1051.53
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ b9b17debc69d27cd55e21ee51a5ba7fc50a426cf, < c7f75d11fe72913d2619f97b2334b083cd7bb955 | ≥ b9b17debc69d27cd55e21ee51a5ba7fc50a426cf, < dc1b438a35773d030be0ee80d9c635c3e558a322 | ≥ b9b17debc69d27cd55e21ee51a5ba7fc50a426cf, < 16d8c44be52e3650917736d45f5904384a9da834 | ≥ b9b17debc69d27cd55e21ee51a5ba7fc50a426cf, < 55fcdd1258faaecca74b91b88cc0921f9edd775d | ≥ b9b17debc69d27cd55e21ee51a5ba7fc50a426cf, < 9dc373f74097edd0e35f3393d6248eda8d1ba99d | ≥ b9b17debc69d27cd55e21ee51a5ba7fc50a426cf, < 8c06f34785068b87e2b560534c77c163d6c6dca7 | ≥ b9b17debc69d27cd55e21ee51a5ba7fc50a426cf, < e407495ba6788a67d1bd41714158c079e340879b | ≥ b9b17debc69d27cd55e21ee51a5ba7fc50a426cf, < 6d72e7c767acbbdd44ebc7d89c6690b405b32b57 | 4.9
  • linux_kernel≥ 4.9, < 4.9.269 | ≥ 4.10, < 4.14.233 | ≥ 4.15, < 4.19.191 | ≥ 4.20, < 5.4.119 | ≥ 5.5, < 5.10.37 | ≥ 5.11, < 5.11.21 | ≥ 5.12, < 5.12.4
Debian1 product
  • linux< 5.10.38-1

3 vendors · 88 products

References

12 links
Show all 12 references