Buffer overflow in Linux Kernel
CVE-2021-33909
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.
Vulnerability class: Integer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.097 (95.5th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 95th percentile — 95.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.097 · newest: 0.097 · change: 0.000
Affected products
- Linux Kernel
- NetApp Hci Management Node
- NetApp Solidfire
- Oracle Communications Session Border Controller — versions 8.2, 8.3, 8.4
- SonicWall Sma1000
- SonicWall Sma1000 Firmware
- Debian Linux — versions 9.0, 10.0
- Fedoraproject Fedora — versions 34
Weakness classification (CWE)
Public proof-of-concept exploits
References
- lists.debian.org/debian-lts-announce/2021/07/msg00016.html (mailing-list, Mailing List, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2021/07/msg00014.html (mailing-list, Mailing List, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2021/07/msg00015.html (mailing-list, Mailing List, Third Party Advisory)
- www.debian.org/security/2021/dsa-4941 (vendor-advisory, Third Party Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- www.openwall.com/lists/oss-security/2021/07/22/7 (mailing-list, Mailing List, Third Party Advisory)
- www.openwall.com/lists/oss-security/2021/08/25/10 (mailing-list, Mailing List, Third Party Advisory)
- www.openwall.com/lists/oss-security/2021/09/17/2 (mailing-list, Mailing List, Third Party Advisory)
- www.openwall.com/lists/oss-security/2021/09/17/4 (mailing-list, Mailing List, Third Party Advisory)
- www.openwall.com/lists/oss-security/2021/09/21/1 (mailing-list, Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-33909?
- CVE-2021-33909 is a high-severity vulnerability in Linux Kernel, classified under Integer Overflow or Wraparound. CVSS score: 7.8/10. Published 2021-07-20.
- How severe is CVE-2021-33909?
- High severity. CVSS v3 base score is 7.8 out of 10.
- Is CVE-2021-33909 known to be exploited?
- 41 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.