Cyber Resilience

CVE-2021-33909

HighPublic PoC

Published: 20 July 2021

Published
20 July 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0178 83.1th percentile
Risk Priority 17 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-33909 is a high-severity Integer Overflow or Wraparound (CWE-190) vulnerability in Linux Linux Kernel. Its CVSS base score is 7.8 (High).

Operationally, ranked in the top 16.9% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

fs/seq_file.c in the Linux kernel 3.16 through 5.13.x before 5.13.4 does not properly restrict seq buffer allocations, leading to an integer overflow, an Out-of-bounds Write, and escalation to root by an unprivileged user, aka CID-8cae8cd89f05.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

linux
linux kernel
3.12.43 — 3.13 · 3.16 — 4.4.276 · 4.5 — 4.9.276
fedoraproject
fedora
34
debian
debian linux
10.0, 9.0
netapp
hci management node
all versions
netapp
solidfire
all versions
oracle
communications session border controller
8.2, 8.3, 8.4, 9.0
sonicwall
sma1000 firmware
≤ 12.4.2-02044

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-787

Out-of-bounds writes that corrupt control flow or inject shellcode are rendered non-executable by the same memory protections.

References