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Vulnerabilities

Vulnerability · CVE-2021-36087

The CIL compiler in SELinux 3.2 has a heap-based buffer over-read in ebitmap_match_any (called indirectly from cil_check_neverallow).

Published Jul 1, 2021 · catalog updated Oct 14, 2026 · selinux project

Check if you run it

No confirmed exploitation is on record for CVE-2021-36087. EPSS is 0.48%. Act only if a listed version of selinux project is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Low3.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.48%
Remediation
Advisory link
Affected products
cpe fedoraproject/fedora · cpe selinux project/selinux

The CIL compiler in SELinux 3.2 has a heap-based buffer over-read in ebitmap_match_any (called indirectly from cil_check_neverallow). This occurs because there is sometimes a lack of checks for invalid statements in an optional block.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe fedoraproject/fedora35
  • cpe selinux project/selinux3.2

How to fix CVE-2021-36087

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2021-36087. EPSS is 0.48%. Act only if a listed version of selinux project is installed.

Which versions are affected?

Compare what you have installed with selinux project/selinux 3.2. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-125: Out-of-bounds Read. EPSS 0.48%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jul 1, 2021 · NIST NVD

    Detected

    The CIL compiler in SELinux 3.2 has a heap-based buffer over-read in ebitmap_match_any (called indirectly from cil_check_neverallow). This occurs because there is sometimes a lack of checks for invalid statements in an optional block.

  2. Oct 14, 2026 · NIST NVD

    Updated

    The CIL compiler in SELinux 3.2 has a heap-based buffer over-read in ebitmap_match_any (called indirectly from cil_check_neverallow). This occurs because there is sometimes a lack of checks for invalid statements in an optional block.

Sources

  • CVE.orgVulnerability recordCVE-2021-36087

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-36087

    30-day exploitation probability 0.5%

    first.org
  • NIST NVDVulnerability recordCVE-2021-36087

    The CIL compiler in SELinux 3.2 has a heap-based buffer over-read in ebitmap_match_any (called indirectly from cil_check_neverallow). This occurs because there is sometimes a lack of checks for invalid statements in an optional block.

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 16, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.