dbcve.org
Debian LinuxOperating system · Debian

CVE-2024-27355

HIGH · 7.5 CVSS v3.1 Published 2024-03-01
Fix available
A fix is available. Upgrade to 1.0.23 / 2.0.47 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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
An issue was discovered in phpseclib 1.x before 1.0.23, 2.x before 2.0.47, and 3.x before 3.0.36. When processing the ASN.1 object identifier of a certificate, a sub identifier may be provided that leads to a denial of service (CPU consumption for decodeOID).

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

A denial of service vulnerability exists in phpseclib's ASN.1 object identifier (OID) decoding function (decodeOID). When processing a certificate's ASN.1 OID, a specially crafted sub identifier can cause excessive CPU consumption, leading to service unavailability. The vulnerability affects versions 1.x before 1.0.23, 2.x before 2.0.47, and 3.x before 3.0.36.

MitigationUpgrade phpseclib to version 1.0.23 or later (1.x), 2.0.47 or later (2.x), or 3.0.36 or later (3.x). If upgrading is not immediately feasible, consider rate limiting or restricting certificate processing from untrusted sources.

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
Debian LinuxOperating system
Affected:= 10.0
PhpseclibApplication
Affected:>= 1.0.0, < 1.0.23>= 2.0.0, < 2.0.47>= 3.0.0, < 3.0.36

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. Locate phpseclib installation
    Search for phpseclib files in the environment: check Composer vendor directory (vendor/phpseclib), PHP include paths, or Debian package system (dpkg -L phpseclib). Look for files containing 'phpseclib' in the filename.
    Affected if phpseclib files are found in the system
  2. Determine installed phpseclib version
    If using Composer, check the version listed in vendor/composer/installed.json or composer.lock. If using Debian package, run 'dpkg -l phpseclib' to see the installed version. Alternatively, check the version.php file within the phpseclib library directory.
    Affected if The version found is 1.x < 1.0.23, 2.x < 2.0.47, or 3.x < 3.0.36
  3. Identify ASN.1 OID decode functionality in use
    Search source code for calls to decodeOID function or ASN1::decodeOID method. Look for code that parses X.509 certificates, public/private keys, or other ASN.1 DER encoded data. Search for 'decodeOID' or 'ASN1' class usage in application source files.
    Affected if The application code calls decodeOID or processes ASN.1 encoded certificates/keys from untrusted sources
  4. Check Debian system package version
    On Debian 10 systems, run 'apt-cache policy phpseclib' to see available package versions, or 'dpkg-query -W phpseclib' to confirm if the package is installed and its version.
    Affected if The Debian phpseclib package version is below the fixed releases (1.0.23, 2.0.47, or 3.0.36)
  5. Verify certificate processing from external sources
    Review application configuration and logs to determine if certificates from untrusted or external sources (such as client certificates, SAML assertions, or JWT tokens) are being processed using phpseclib.
    Affected if The application processes certificates or ASN.1 data originating from untrusted or external sources

A system is affected if phpseclib versions 1.x < 1.0.23, 2.x < 2.0.47, or 3.x < 3.0.36 are installed AND the decodeOID function is used to process ASN.1 OIDs from certificates, enabling a specially crafted OID to trigger excessive CPU consumption.

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 1.0.23 / 2.0.47 / 3.0.36 or later
Fixed in 1.0.232.0.473.0.36
Interim mitigation

Upgrade phpseclib to version 1.0.23 or later (1.x), 2.0.47 or later (2.x), or 3.0.36 or later (3.x). If upgrading is not immediately feasible, consider rate limiting or restricting certificate processing from untrusted sources.

Recommended fix High confidence

phpseclib 1.0.23 (for 1.x), 2.0.47 (for 2.x), or 3.0.36 (for 3.x)

  1. 1. Identify the phpseclib major version in use (1.x, 2.x, or 3.x) by checking your composer.json or vendor directory.
  2. 2. For phpseclib 1.x: Update to version 1.0.23 or later (e.g., composer require phpseclib/phpseclib:^1.0.23).
  3. 3. For phpseclib 2.x: Update to version 2.0.47 or later (e.g., composer require phpseclib/phpseclib:^2.0.47).
  4. 4. For phpseclib 3.x: Update to version 3.0.36 or later (e.g., composer require phpseclib/phpseclib:^3.0.36).
  5. 5. Run composer update to apply the changes.
  6. 6. Test the application to ensure the upgrade does not break functionality.

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

Fix this in Debian Linux Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,720
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Scan for this in your stack

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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-2024-27355 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