CVE-2026-28809Network attack vector

Local file disclosure via pre-signature entity expansion

Published Mar 23, 2026 · Updated Mar 23, 2026

XXE in esaml all versions allows remote attackers to read local files and initiate SSRF through crafted SAML messages. Before signature verification, xmerl_scan:string/2 expands external entities in attacker-controlled XML because esaml does not disable entities. Exposure requires SAML processing on Erlang/OTP before 27; failed signatures discard documents, but file data can reach logs or errors.

CVSS severity6.3
Medium
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

XXE in esaml all versions allows remote attackers to read local files and initiate SSRF through crafted SAML messages. Before signature verification, xmerl_scan:string/2 expands external entities in attacker-controlled XML because esaml does not disable entities. Exposure requires SAML processing on Erlang/OTP before 27; failed signatures discard documents, but file data can reach logs or errors.

The record

CVE
CVE-2026-28809
Published
Mar 23, 2026
Updated
Mar 23, 2026
Vendor
Dropbox
Product
esaml
Classifications
CWE-611, CAPEC-201, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Dropbox · esamlAffected versions are unavailable in this record.
arekinath · esamlAffected versions are unavailable in this record.
handnot2 · esamlAffected versions are unavailable in this record.

Published CVSS scores

6.3Erlang Ecosystem FoundationCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-611Improper Restriction of XML External Entity Reference
CAPEC-201Serialized Data External Linking
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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