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CVE-2026-129427VulnerabilityPublished

Stored XSS via avatar upload chained with an authentication bypass in /Attachments leads to ATO in Cervantes version

Source GCVE Database

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Authoritative record:CVE-2026-129427· High 8.7

Not known to be exploited · CVSS 8.7 High.

Data as of 14 Nov 2026, 13:17 UTC

CVSS 3.1 base score
8.7High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (Grayback)CVSS 3.18.7
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 14 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 14 Nov 2026.

What to do

Affected software

ProductAffectedFixed in
CervantesSeccervantesAffected
  • ≥ alpha 0.3, ≤ 1.3-beta
Fixed in–

AI-suggested

Until a fix is available, restrict avatar upload functionality and monitor for suspicious activity related to /Attachments endpoint. Apply strict input validation and sanitization on avatar uploads and authentication mechanisms as temporary mitigations.

Description

Cervantes version v1.3-beta contains a stored cross-site scripting (XSS) vulnerability via avatar upload combined with an authentication bypass in the /Attachments endpoint. This flaw could allow an attacker to execute arbitrary code in another user's browser with elevated privileges, potentially leading to account takeover (ATO). The vulnerability has a high severity rating with a CVSS score of 8.7.

References

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