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01 Record

CVE-2026-25540

Mastodon's signature-dependent ActivityPub collection responses cached under signature-independent keys (Web Cache Poisoning via `Rails.cache`)

MediumPUBLISHEDCNA: GitHub_M
CNA base score6.5 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

02 Description

Mastodon's signature-dependent ActivityPub collection responses cached under signature-independent keys (Web Cache Poisoning via `Rails.cache`)

03 Exploitation and scoring

Exploitation
Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
SSVC decision
  • ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
  • AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
  • Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
0.44% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 38.5% of scored records. A rank, not a probability.
NVD base score
6.5 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
NVD analysis status
Analyzed. NVD last modified this record on 2026-06-17.
Red Hat severity
No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2026-02-04 21:42Z8 MO AGO
Last updated
2026-02-05 18:30Z8 MO AGO
Reserved
2026-02-02
Assigning CNA
GitHub_M
Record state
PUBLISHED
Severity
Medium (CVSS 6.5)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
Weaknesses
  • CWE-524Use of Cache Containing Sensitive InformationBase
Data version
5.2
Document digest
ea68a01e56564bcc745994471da9f925e7bcc8e2337f570bf5ce4fc93596bc2c

05 Affected products

VendorProductVersionsPlatforms
mastodonmastodon< 4.3.19, < 4.4.13, < 4.5.6—

06 References