CVE-2026-73638 Imager versions from 0.45_02 before 1.035 for Perl read outside the EXIF block via unchecked start offsets in tiff_load_ifd.
Attackers can read memory outside EXIF blocks or crash applications using the Imager Perl library by supplying crafted TIFF images with unchecked offsets.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-73638?
CVE-2026-73638 is a medium-severity memory corruption vulnerability, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Imager versions from 0.45_02 before 1.035 for Perl read outside the EXIF block via unchecked start offsets in tiff_load_ifd.
tiff_load_ifd() validates an IFD entry's data by checking that `entry->offset + entry->size` stays within the EXIF block, and never checks the start offset itself. Where that sum is not the real end of the data, the check passes with the entry starting outside the block.
Through 1.032 `entry->offset` is a plain int, so on the usual two's-complement implementations an offset with the high bit set converts to negative and the sum can land back inside the block. From 1.033 the field is a size_t and the addition wraps only where size_t is 32 bits. The IFD's own start offset is checked the same way and wraps where unsigned long is 32 bits, which includes 64-bit Windows.
Any caller of Imager->read() on an attacker-supplied image may receive EXIF tags holding bytes from outside the block, or crash the process.
Weakness: CWE-125
Which versions are affected by CVE-2026-73638?
How do I fix CVE-2026-73638?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-73638 being exploited?
There is no known exploitation of CVE-2026-73638 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-73638, GHSA-j47j-8w8p-3mmc, UBUNTU-CVE-2026-73638.