CVE-2026-111687: WeRSS (we-mp-rss) through 1.5.3 RCE via template Parameter in /rss Endpoint

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-16 · updated 2026-10-16
Weakness: CWE-95

Description

WeRSS (we-mp-rss) through 1.5.3 contains a remote code execution vulnerability that allows unauthenticated attackers to run code via the template parameter of the public GET /rss/{feed_id} endpoint. Attackers can supply a non-built-in ext value and a {{=expression}} template whose object-subclass traversal bypasses the eval denylist to run OS commands as the service account.

Affected products

rachelos we-mp-rss: through 1.5.3

References

https://github.com/rachelos/we-mp-rss/blob/v1.5.3/apis/rss.py#L185-L198
https://github.com/rachelos/we-mp-rss/blob/v1.5.3/core/lax/template_parser.py#L1150-L1166
https://hackmd.io/@hieuPenguinnn/werss-rss-template-unauth-ssti-rce
https://www.vulncheck.com/advisories/werss-we-mp-rss-through-1.5.3-rce-via-template-parameter-in-rss-endpoint
https://hackmd.io/@hieuPenguinnn/werss-rss-template-unauth-ssti-rce

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