CVE-2025-68131Public exploitNetwork attack vector

Cross-message data disclosure via persistent shared references

Published Dec 31, 2025 · Updated Dec 31, 2025

Information disclosure in cbor2 3.0.0 through 5.7.1 allows remote attackers to read prior decoded values via crafted CBOR shared references. CBORDecoder's decode_from_bytes and stream replacement paths leave the shareables list populated after a top-level decode, so tag 29 resolves tag 28 values from an earlier message. Exposure requires decoder reuse across trust boundaries after a trusted message used value sharing; disclosure is limited to retained shareable values.

CVSS severity7.5
High
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in cbor2 3.0.0 through 5.7.1 allows remote attackers to read prior decoded values via crafted CBOR shared references. CBORDecoder's decode_from_bytes and stream replacement paths leave the shareables list populated after a top-level decode, so tag 29 resolves tag 28 values from an earlier message. Exposure requires decoder reuse across trust boundaries after a trusted message used value sharing; disclosure is limited to retained shareable values.

The record

CVE
CVE-2025-68131
Published
Dec 31, 2025
Updated
Dec 31, 2025
Vendor
Alex Grönholm
Product
cbor2
Classifications
CWE-212
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 31, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 31, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 3.0.0, < 5.8.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Alex Grönholm · cbor2version=>= 3.0.0, < 5.8.0

Published CVSS scores

5.5GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-212Improper Removal of Sensitive Information Before Storage or Transfer

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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