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
Imager versions from 0.4502 before 1.035 for Perl read outside the EXIF block via unchecked start offsets in tiffloadifd.
tiffloadifd() 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 sizet and the addition wraps only where sizet 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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Perl Imagerto a version that resolves this vulnerability.Fixed in 1.035
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
Deployments using Imager versions from 0.45_02 before 1.035 are affected when they call Imager->read() on attacker-supplied images. The impact is exposure of bytes outside the EXIF block through EXIF tags or a process crash.
What does an attacker need to exploit it?
An attacker needs to provide a crafted image that is processed by Imager->read(). The malformed EXIF IFD offsets must bypass the incomplete bounds check, including through signed conversion in versions through 1.032 or integer wrapping on affected 32-bit type configurations in later versions.
Which platform and version details affect exploitability?
Through version 1.032, a high-bit offset can become negative on usual two's-complement systems and allow the checked sum to fall inside the EXIF block. From 1.033, entry-offset wrapping requires a 32-bit size_t; checking the IFD start offset can also wrap with a 32-bit unsigned long, including on 64-bit Windows.