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VulnerabilityPublished

CVE-2026-100836: Contrast through 1.20.0 contains a panic vulnerability in the transit-engine endpoint's ciphertextContainer.UnmarshalJSON function that fails to

Affects contrastSource GCVE Database

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Authoritative record:CVE-2026-100836· Medium 5.3

Not known to be exploited · CVSS 5.3 Medium : upgrade to 1.20.1 when convenient.

Data as of 8 Nov 2026, 23:24 UTC

CVSS 4.0 base score
5.3Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 1.20.1
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

  1. Disclosed: evidence found.

    CVE published 27 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: evidence found.

    CISA SSVC: proof of concept public

  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

Timeline

  1. CVE ID reserved

    by VulnCheck

    , 2 hours before disclosure

  2. CVE published

    on cve.org

    , t = 0

  3. CISA SSVC assessment

    proof of concept public

    , 39 hours after disclosure

  4. In Threat Radar

    record ingested

    , 29 days after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA SSVC, the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.

What to do

Upgrade edgelesssys/contrast to 1.20.1.

Affected software

ProductAffectedFixed in
GitHubedgelesssys/contrastpkg:github/edgelesssys/contrastOther threatsAffected
  • <1.20.1
Fixed in
  • 1.20.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade to Contrast version 1.20.1 or later where this issue is fixed. If upgrading immediately is not possible, monitor for unusual log spam and request failures related to the transit-engine endpoint and restrict access to authenticated workloads with mesh certificates to trusted entities only.

Description

Contrast versions up to 1.20.0 contain a medium severity vulnerability (CVE-2026-100836) in the transit-engine endpoint's ciphertextContainer.UnmarshalJSON function. The flaw is due to improper validation of the length of decoded ciphertext before slicing, which can cause a runtime panic. An authenticated workload with a valid mesh certificate can exploit this by submitting a short base64-encoded ciphertext, resulting in log spam and request failures. The process does not crash, and no confidentiality or integrity impact is reported.

References

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