Is there a public exploit for CVE-2026-59884?

No public exploit for CVE-2026-59884 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-59884?

CVE-2026-59884 scores CVSS 7.5 (v3.1), rated high. EPSS puts the chance of exploitation in the next 30 days at 0.62%.

What does CVE-2026-59884 affect?

CVE-2026-59884 affects pyasn1 pyasn1.

7.5 High

pyasn1 is a generic ASN.1 library for Python.

CVE-2026-59884

pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER decoder shared by the CER and DER codecs parses long-form tags by accumulating continuation octets without an upper bound on the tag ID size, allowing a crafted input to force construction of an arbitrarily large integer with CPU cost growing quadratically and to trigger unhandled ValueError exceptions in Python 3.11+ error formatting paths. Any application decoding untrusted BER, CER, or DER input is affected. This issue is fixed in version 0.6.4.

Assessment

CVSS: 7.5 (v3.1)
Severity: High
EPSS: 0.62% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 14 July 2026
Last updated: 21 July 2026
Affected: pyasn1 · pyasn1
Weakness: CWE-400
Assigner: security-advisories@github.com

CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

At the source

References

Community proofs of concept

No community proof of concept yet. If you have one for a published vulnerability and the right to share it, add it below — it will appear here once reviewed.

Submit a proof of concept

Only for publicly disclosed vulnerabilities, and only material from testing you were authorised to perform. This platform does not buy, sell, or broker exploits — see earning from vulnerability research for legitimate bounty programs. Submissions are reviewed before they appear. Text only; do not include live credentials, personal data, or anything targeting systems you are not permitted to test.

Title *

Proof of concept *

Write-up (optional)

Affected versions (optional)

Name or handle (optional)

References (optional, one URL per line)

Licence for your contribution *

Private contact (optional, never shown)

Before you submit * This vulnerability is already publicly disclosed (it has a published CVE). This material comes only from testing I was authorised to perform. I have the legal right to publish this content and am not breaching any agreement by doing so. It contains no live credentials, personal data, or anything targeting systems I am not authorised to test. I understand it will be reviewed before it appears publicly and may be rejected. I agree to the submission terms.

What is 7 + 3? *

Query this programmatically

Agents can read this through the MCP endpoint, or over HTTP:

curl https://cve.zerocrew.in/api/cve/CVE-2026-59884