CVE-2026-28809 XXE in esaml SAML library allows local file read and potential SSRF
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-28809?
CVE-2026-28809 is a medium-severity vulnerability in Jump-App esaml, published on 23 Mar 2026.
Official description
XML External Entity (XXE) vulnerability in esaml (and its forks) allows an attacker to cause the system to read local files and incorporate their contents into processed SAML documents, and potentially perform SSRF via crafted SAML messages.
esaml parses attacker-controlled SAML messages using xmerl_scan:string/2 before signature verification without disabling XML entity expansion. On Erlang/OTP versions before 27, Xmerl allows entities by default, enabling pre-signature XXE attacks. An attacker can cause the host to read local files (e.g., Kubernetes-mounted secrets) into the SAML document. If the attacker is not a trusted SAML SP, signature verification will fail and the document is discarded, but file contents may still be exposed through logs or error messages.
This issue affects all versions of esaml, including forks by arekinath, handnot2, and dropbox. Users running on Erlang/OTP 27 or later are not affected due to Xmerl defaulting to entities disabled.
Weakness: CWE-611
Which versions are affected by CVE-2026-28809?
3 open source packages ship an affected version, including esaml. It affects 4 products.
| Package | Affected | Fixed in |
|---|---|---|
esaml Hex | All versions | None |
esaml Hex | All versions to 4.6.0 | None |
esaml Hex | All versions to 4.6.0 | None |
Products include Arekinath Esaml, Dropbox Esaml, Handnot2 Esaml, Jump-App Esaml.
How do I fix CVE-2026-28809?
No fix has been published for CVE-2026-28809 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-28809 being exploited?
There is no known exploitation of CVE-2026-28809 in the wild and no public exploit code.
Sources
Also known as EEF-CVE-2026-28809, GHSA-4g2h-vm7x-747c.