Is CVE-2026-121261 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-121261 being exploited in the wild.

How severe is CVE-2026-121261?

Medium severity, with a CVSS score of 4.3, published 3 November 2026.

Which products and versions are affected?

phpMyAdmin ShapeFile up to 4.0.1.

Is there a fix for CVE-2026-121261?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-121261 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-121261?

Check whether you run phpMyAdmin ShapeFile at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-121261: phpMyAdmin ShapeFile infinite loop in SHP file parsing

CVE-2026-121261 · Severity: medium · CVSS 4.3 · Published 2026-11-03

phpMyAdmin ShapeFile is a library for reading ESRI shapefile data, commonly used in database management tools. A malformed shapefile with truncated content can cause the parser to enter an infinite loop, consuming 100% of a CPU core indefinitely. An attacker who can upload or supply a crafted shapefile through any application using this library can trigger a denial-of-service condition with minimal effort—a 112-byte file is sufficient.

Vendors: phpMyAdmin.

Quick answers

Is CVE-2026-121261 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-121261 being exploited in the wild.
How severe is CVE-2026-121261?: Medium severity, with a CVSS score of 4.3, published 3 November 2026.
Which products and versions are affected?: phpMyAdmin ShapeFile up to 4.0.1.
Is there a fix for CVE-2026-121261?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-121261 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-121261?: Check whether you run phpMyAdmin ShapeFile at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The ShapeRecord::loadFromFile method contains an infinite loop when parsing a .shp record whose declared content length exceeds the actual bytes remaining in the file. The vulnerability exists because readSHP() returns an empty string at EOF rather than false, so strlen("") = 0 means the loop counter never advances, creating an unreachable exit condition (CWE-835). Remote attackers can trigger this without authentication by uploading or providing a malformed shapefile to any application that calls ShapeFile::loadFromFile().

Affected products

phpMyAdmin ShapeFile up to 4.0.1

Timeline

2026-11-03: disclosed: Public disclosure; exploit available
2026-10-07: other: Vulnerability identified and reproducer generated

References

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