CVE-2026-77781

Description

Tie::Hash::Regex versions before 2.0.0 for Perl will throw an exception on unparseable lookup keys. The FETCH, EXISTS and DELETE methods throw an exception when on malformed regular expressions. Each method falls back to a regex match when the key is not already stored in the hash, compiling the caller's key with a bare qr// and no eval guard. A key that is not a valid regular expression pattern, such as a single unmatched bracket, dies. An application that looks up externally supplied strings in a tied hash will die on an invalid key.

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EPSS — Exploit Prediction

0.0024

Probability of exploitation

0.15%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-248 CWE-248

References

Other References

https://github.com/davorg-cpan/tie-hash-regex/commit/4239732cb76233543e2ded8ff5e0f238af152e0c.patch https://metacpan.org/release/DAVECROSS/Tie-Hash-Regex-2.0.0/source/Changes http://www.openwall.com/lists/oss-security/2026/08/22/2

Frequently Asked Questions

What is CVE-2026-77781? +

Tie::Hash::Regex versions before 2.0.0 for Perl will throw an exception on unparseable lookup keys. The FETCH, EXISTS and DELETE methods throw an exception when on malformed regular expressions. Each method falls back to a regex match when the key is not already stored in the hash, compiling the caller's key with a bare qr// and no eval guard. A key that is not a valid regular expression pattern, such as a single unmatched bracket, dies. An application that looks up externally supplied strings in a tied hash will die on an invalid key.

How do I check if I'm vulnerable to CVE-2026-77781? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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