Use After Free in Linux Kernel
CVE-2021-33033
The Linux kernel before 5.11.14 has a use-after-free in cipso_v4_genopt in net/ipv4/cipso_ipv4.c because the CIPSO and CALIPSO refcounting for the DOI definitions is mishandled, aka CID-ad5d07f4a9cd. This leads to writing an arbitrary value.
Vulnerability class: Use-After-Free
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: 0.006 (45.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 45th percentile — 45.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: +0.000
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.7 (Patch, Mailing List, Vendor Advisory)
- syzkaller.appspot.com/bug (Exploit, Mailing List, Third Party Advisory)
- sites.google.com/view/syzscope/kasan-use-after-free-read-in-cipso_v4_genopt (Exploit, Third Party Advisory)
- git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ (Patch, Mailing List, Vendor Advisory)
- git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ (Patch, Mailing List, Vendor Advisory)
- cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.11.14 (Patch, Mailing List, Vendor Advisory)
Frequently asked questions
- What is CVE-2021-33033?
- CVE-2021-33033 is a high-severity vulnerability in Linux Kernel, classified under Use After Free. CVSS score: 7.8/10. Published 2021-05-14.
- How severe is CVE-2021-33033?
- High severity. CVSS v3 base score is 7.8 out of 10.
- Is CVE-2021-33033 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.