7.8

CVE-2021-47040: io_uring: fix overflows checks in provide buffers

Modified
AliasesUBUNTU-CVE-2021-47040DEBIAN-CVE-2021-47040
Published 28-02-2024Last modified 05-08-2026

Vulnerability summary

CVE-2021-47040 is a high (CVSS 7.8) vulnerability in linux. EPSS estimates a 0.26% chance of exploitation in the next 30 days, higher than 18% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 7.8, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
7.8/10
010
High · v3.1 (CVE.org)
EPSS score
0.26%
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

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: io_uring: fix overflows checks in provide buffers Colin reported before possible overflow and sign extension problems in io_provide_buffers_prep(). As Linus pointed out previous attempt did nothing useful, see d81269fecb8ce ("io_uring: fix provide_buffers sign extension"). Do that with help of check_<op>_overflow helpers. And fix struct io_provide_buf::len type, as it doesn't make much sense to keep it signed.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.26%

Chance of exploitation in the next 30 days

Percentile

18%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.26% 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: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu62 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≥ efe68c1ca8f49e8c06afd74b699411bfbb8ba1ff, < cbbc13b115b8f18e0a714d89f87fbdc499acfe2d | ≥ efe68c1ca8f49e8c06afd74b699411bfbb8ba1ff, < 51bf90901952aaac564bbdb36b2b503050c53dd9 | ≥ efe68c1ca8f49e8c06afd74b699411bfbb8ba1ff, < 84b8c266c4bfe9ed5128e13253c388deb74b1b03 | ≥ efe68c1ca8f49e8c06afd74b699411bfbb8ba1ff, < 38134ada0ceea3e848fe993263c0ff6207fd46e7 | 5.8
  • linux_kernel≥ 5.8, < 5.10.37 | ≥ 5.11, < 5.11.21 | ≥ 5.12, < 5.12.4
Debian1 product
  • linux< 5.10.38-1

3 vendors · 65 products

References

8 links