CVE-2026-65655Temporal UI Server may set OAuth credential cookies without Secure behind a TLS-terminating reverse proxy
- 2.3LowCVSS base score
- 0.37%Exploitation in 30 daysEPSS · top 68% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
When OAuth authentication is enabled and browser-facing TLS terminates at a reverse proxy that forwards the callback to Temporal UI Server over HTTP, affected versions derive authentication-cookie Secure attributes from the proxy-to-server connection. Temporal UI Server can therefore issue access-token cookies, and refresh-token cookies when provided by the identity provider, without Secure even though the browser completed login over HTTPS. A victim who visits attacker-controlled content while a credential remains live may expose that credential only if the attacker can also steer traffic for the UI hostname, prevent the browser's HTTPS connection from succeeding, serve the hostname over HTTP, and read a later same-site plaintext request. A malicious website alone cannot read the cookie, and passive observation of a successful TLS connection is insufficient. Effective HSTS, a blocking HTTPS-only warning, or TLS re-encryption between the proxy and Temporal UI Server prevents the demonstrated disclosure path. A recovered credential may be replayed within the victim's assigned permissions. Refresh-token replay additionally depends on the identity provider's issuance, expiry, rotation, and reuse-detection behavior.
Timeline
ID reserved
By Temporal
- 20 days later
· 20 days later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| TemporalCNA (assigner) | 4.0 | Low2.3 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N |
| NVDNVD · Deferred | 4.0 | Low2.3 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.37% · top 68% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Low 2.3.
Affected products
Temporal Technologies, Inc. · Temporal UI Server
- affected 2.7.0 – < 2.53.2
What to do
Solution: Upgrade to Temporal UI Server v2.53.2 or later. The fix derives the authentication-cookie Secure attribute from the configured browser-facing OAuth callback URL instead of the proxy-to-server connection and applies that decision consistently to all authentication cookies.
Workaround: Configure TLS between the reverse proxy and Temporal UI Server, enforce HSTS for the public UI hostname, and block plaintext HTTP. These controls prevent the demonstrated disclosure path but do not correct the configuration-dependent cookie attribute.
References
References8
- Access-token cookie implementation introduced in v2.7.0 (opens in a new tab)
- Refresh-token cookie implementation introduced in v2.45.2 (opens in a new tab)
- Affected OAuth credential-cookie implementation in v2.53.1 (opens in a new tab)
- Affected route-cookie implementation in v2.53.1 (opens in a new tab)
- Latest confirmed affected release (opens in a new tab)release-notes
- Fix pull request (opens in a new tab)patch
- Fix mirrored to Temporal UI Server (opens in a new tab)patch
- First fixed release (opens in a new tab)release-notes
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-56924 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-65655)Record last updated .