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CVE-2025-68131

CBORDecoder reuse can leak shareable values across decode calls

Public exploit available. Not confirmed exploited in the wild yet. Fixed in 5.8.0.

CVSS 3.17.5HighEPSS percentile39th0.5% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
Public exploit: 2 sourcesFix5.8.0Upgrade to this build

Published Updated Sources: CVE.org, NVD, GitHub

NVD CVE.org

What to do

Find your product and version, then upgrade to the build on the right.

  • Agronholm Cbor2Affected: >= 3.0.0, < 5.8.0Upgrade to: not statedStated by: CVE record
  • PyPI cbor2Affected: ≥ 3.0.0, < 5.8.0Upgrade to: 5.8.0Stated by: GitHub advisory

Versions as the sources state them. Full version matrix after sign-in

Check it yourselfA free OpenVAS check exists for this CVE. Run it against your hosts.Is your organisation exposed?Request an assessment to establish which checks fit your systems.

What it is

From the CVE record

cbor2 provides encoding and decoding for the Concise Binary Object Representation (CBOR) serialization format. Starting in version 3.0.0 and prior to version 5.8.0, whhen a CBORDecoder instance is reused across multiple decode operations, values marked with the shareable tag (28) persist in memory and can be accessed by subsequent CBOR messages using the sharedref tag (29). This allows an attacker-controlled message to read data from previously decoded messages if the decoder is reused across trust boundaries. Version 5.8.0 patches the issue.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS39th
Public exploit
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

2 sources with a proof of concept or module.

Exploit links, PoCs and Metasploit modules after sign-in
EPSS

0.5% chance of exploitation activity in the next 30 days, which ranks it in the 39th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

The patch came 63 days before any public exploit.

  1. OpenVAS check added
  2. Public exploit / PoCsource: github-poc
  3. Patch availablerecord updated
  4. Publishedweakness classified, att&ck mapped

Affected products

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

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

Scored 7.5 by NVD.

How it is reached

  • Attack Vector NetworkExploitable remotely over the network without any special conditions
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required NoneNo authentication required — anyone can exploit this
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality HighTotal information disclosure — all data in the component is compromised
  • Integrity NoneNo integrity impact
  • Availability NoneNo availability impact

Weaknesses

ATT&CK techniques

Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.

Sources

References in the record

And 3 more references. See all after sign-in

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