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Pyasn1Application

CVE-2026-59885

HIGH · 7.5 CVSS v3.1 Published 2026-07-14
Fix available
A fix is available. Upgrade to 0.6.4 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click Patch available 5 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER, CER, and DER decoders process OBJECT IDENTIFIER and RELATIVE-OID values in quadratic time relative to the number of arcs, so a small crafted payload containing an OID with many arcs consumes excessive CPU per decode() call and can deny service to applications that decode untrusted ASN.1 data. The corresponding encoders have the same quadratic behavior when an application re-encodes previously decoded attacker-supplied values. This issue is fixed in version 0.6.4.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The pyasn1 library's BER, CER, and DER decoders process OBJECT IDENTIFIER and RELATIVE-OID values with quadratic time complexity relative to the number of arcs. A crafted ASN.1 payload containing an OID with many arcs causes excessive CPU consumption, leading to denial of service. The encoders exhibit the same quadratic behavior when re-encoding attacker-supplied decoded values.

MitigationUpdate pyasn1 to version 0.6.4 or later to remediate this vulnerability.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Pyasn1Application
Affected:< 0.6.4

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check if pyasn1 is installed
    Run `pip show pyasn1` or `pip list | grep pyasn1` to see if the package is present in your environment
    Affected if pyasn1 is not installed means you are not affected, but if it appears in the output proceed to version check
  2. Determine the installed pyasn1 version
    Run `pip show pyasn1` and note the Version field, or run `python -c "import pyasn1; print(pyasn1.__version__)"`
    Affected if The version shown is less than 0.6.4 (for example 0.6.3, 0.6.0, 0.5.0, etc.)
  3. Verify the vulnerability applies to your use case
    Determine if your application or service parses BER, CER, or DER encoded ASN.1 data from untrusted sources using the pyasn1 library's decoder functions
    Affected if You process untrusted ASN.1 OBJECT IDENTIFIER or RELATIVE-OID values with a pyasn1 version below 0.6.4

You are affected if pyasn1 version below 0.6.4 is installed and you process ASN.1 data from untrusted sources using the BER, CER, or DER decoders or re-encode decoded OID/RELATIVE-OID values.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 0.6.4 or later
Fixed in 0.6.4
Vendor patch github.com →
Interim mitigation

Update pyasn1 to version 0.6.4 or later to remediate this vulnerability.

Recommended fix High confidence

pyasn1 version 0.6.4

  1. Check the current installed version of pyasn1 in your environment using: pip show pyasn1
  2. Upgrade pyasn1 to version 0.6.4 or later using: pip install --upgrade 'pyasn1>=0.6.4'
  3. Verify the upgrade was successful by running: pip show pyasn1 and confirming the version is 0.6.4 or higher
  4. If you use pyasn1 as a dependency in a project, update your requirements.txt or setup.py to specify 'pyasn1>=0.6.4'
  5. Rebuild and redeploy any applications that depend on pyasn1 after upgrading
  6. Test your applications to ensure they still function correctly after upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Pyasn1 Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,390
Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-59885 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data