CVE-2026-9390 XML::Sig versions before 0.71 for Perl allow XPath injection in ID lookup
Attackers can inject XPath expressions to bypass XML signature verification, allowing them to validate malicious documents as legitimate.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-9390?
CVE-2026-9390 is a critical code injection vulnerability in TIMLEGGE XML::Sig, published on 3 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
XML::Sig versions before 0.71 for Perl allow XPath injection in ID lookup.
verify() and _get_signed_xml() in lib/XML/Sig.pm build XPath expressions by concatenating the SignedInfo/Reference/@URI value read from the document being verified. The value is neither escaped nor checked against the NCName grammar that XML requires of an ID, so a URI containing a single quote closes the string literal in the generated expression and appends arbitrary XPath operators.
A crafted URI can make the lookup match elements the reference does not name, or every element in the document, so which node is selected for digest verification is decided by the injected expression rather than by the reference.
Which versions are affected by CVE-2026-9390?
It affects 1 product.
Products include Xml\ \.
How do I fix CVE-2026-9390?
No fix has been published for CVE-2026-9390 yet. Limit exposure of the affected software until one is available.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-9390 being exploited?
There is no known exploitation of CVE-2026-9390 in the wild and no public exploit code.
Other vulnerabilities in TIMLEGGE XML::Sig
Sources
Also known as GHSA-mhmm-7px6-jx3j.