---
title: "CVE-2026-91123: Discourse - Open Redirect"
description: "Discourse < 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0 contains an open redirect caused by improper handling of backslashes in iframe src traversal guard, letting attackers load unauthorized iframe content, exploit requires crafted iframe source."
url: https://panop.io/threat-heartbeat/CVE-2026-91123/
---

# CVE-2026-91123 Discourse - Open Redirect

Discourse < 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0 contains an open redirect caused by improper handling of backslashes in iframe src traversal guard, letting attackers load unauthorized iframe content, exploit requires crafted iframe source.

CVSS base score 7.2 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.29% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-91123)

## Details

Type

Open Redirect

Impact

Open Redirect, Information Disclosure

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Published

24 September 2026

Updated

15 October 2026

Weakness

[CWE-22](https://cwe.mitre.org/data/definitions/22.html)

## Vendor fix

Update to versions 2026.1.8, 2026.6.3, 2026.7.2, or 2026.8.0.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-91123](https://nvd.nist.gov/vuln/detail/CVE-2026-91123)
- [https://github.com/discourse/discourse/commit/142f5155ad8e56ddb8012c4e70c69a03dedc0579](https://github.com/discourse/discourse/commit/142f5155ad8e56ddb8012c4e70c69a03dedc0579)
- [https://github.com/discourse/discourse/pull/42882](https://github.com/discourse/discourse/pull/42882)
- [https://github.com/discourse/discourse/security/advisories/GHSA-6pwj-wgg8-4rjc](https://github.com/discourse/discourse/security/advisories/GHSA-6pwj-wgg8-4rjc)
- [https://github.com/discourse/discourse/commit/042d7b159beda4f74d23e245e8b2e396d9ff8318](https://github.com/discourse/discourse/commit/042d7b159beda4f74d23e245e8b2e396d9ff8318)
- [https://github.com/discourse/discourse/commit/097ce5600a2d74d9c68e57974597ab2684bd2a24](https://github.com/discourse/discourse/commit/097ce5600a2d74d9c68e57974597ab2684bd2a24)
- [https://github.com/discourse/discourse/commit/0b5a27e689925edce9ba9b14110022435d2b94be](https://github.com/discourse/discourse/commit/0b5a27e689925edce9ba9b14110022435d2b94be)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

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