VulnerabilityModified

CVE-2026-28809

MEDIUM 6.3EPSS 0.28%

Does this matter?

Lower severity and a low EPSS score (0.28%). Track it; it rarely justifies an emergency change on its own.

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.

CVSS 4.0: 6.3 MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/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/M
EPSS: 0.28% probability · 21th percentile
CISA KEV: Not listed
Weakness: CWE-611
Affected: arekinath/esaml · dropbox/esaml · handnot2/esaml · jump-app/esaml
Source: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db

References

https://cna.erlef.org/cves/CVE-2026-28809.htmlPatch, Third Party Advisory
https://github.com/Jump-App/esaml/commit/bab85efde7c136911402a881ca55173759467a26Patch
https://osv.dev/vulnerability/EEF-CVE-2026-28809Third Party Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.