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Vulnerability · Published Mar 23, 2026 · Assigned by EEF

CVE-2026-28809XXE in esaml SAML library allows local file read and potential SSRF

Medium 6.3

In plain English

A medium-severity XML external entity in esaml from arekinath. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 21% of all known vulnerabilities).

Severity (CVSS 4.0)6.3Medium
Exploit odds (30 days)0.3%top 78.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

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.

Affected products (as reported)

VendorProductVersions
dropbox esaml see references
arekinath esaml see references
handnot2 esaml see references
dropbox esaml see references
Jump-App esaml deeb84378d5c82153b470e99d24f77c38afca14a – before bab85efde7c136911402a881ca55173759467a26

Weakness: CWE-611 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

References