CVE WatchOct 30, 2026

CVE-2026-61626

libass is a portable subtitle renderer for the ASS/SSA (Advanced Substation Alpha/Substation Alpha) subtitle format. From 0.17.4 until 0.17.

CVSS

—

No CVSS

EPSS

—

KEV

—

Exploit Today

—

0-100

Published: Oct 30, 2026 · Last modified: Oct 30, 2026 · CWE-787

EPSS · 30d

Not enough EPSS history yet.

Technical description

libass is a portable subtitle renderer for the ASS/SSA (Advanced Substation Alpha/Substation Alpha) subtitle format. From 0.17.4 until 0.17.5, libass event pruning does not guard negative Matroska `ReadOrder` values, allowing an attacker to clear arbitrarily many bits to zero at attacker-controlled positions near the NULL pointer. Exploitation requires a malicious Matroska stream loaded through `ass_process_chunk`, enabled read-order checking, and later pruning of the malicious events. Read-order checking is enabled by default unless `ass_set_check_readorder` is called with zero; pruning must occur explicitly through `ass_prune_events` or through automatic pruning previously enabled with `ass_configure_prune`. On common systems with arithmetic right shift, 32-bit int values, the upper address region reserved to the kernel, and matching binary/kernel architecture, the expected consequence is denial of service. More extensive exploitation on uncommon systems is theoretical and strongly constrained by the target addresses, bit-clearing-only mutation, and ASLR. This issue is fixed in version 0.17.5.

Official references

Related CVEs

CVECVSSEPSSKEVRExploitTitleMod.

CVE-2026-1040677.8 HIG

—

———Scribus before 1.6.7 contains an out-of-bounds memory access vulnerability in the importsvm plugin that fails to verify bitmap and transparency mask dimensions match. Attackers can supply a crafted SVM file with mismatched mask dimensions to trigger heap reads and writes, causing crashes or code execution as the user.5h CVE-2026-1040667.8 HIG

—

———Scribus before 1.6.7 contains a heap buffer overflow vulnerability in the Mac PICT image loader and import plugin when unpacking 4-bit indexed pixel data. Attackers can supply a crafted PICT file with inconsistent width and row data that, when placed or imported, writes out of bounds, causing crashes or code execution.5h CVE-2026-1040657.8 HIG

—

———Scribus before 1.6.7 contains an out-of-bounds write vulnerability in the importdrw Micrografx Draw plugin that uses an unvalidated y offset to select image scanlines. Attackers can craft a DRW file that, when imported by a user, writes decoded bitmap data outside the heap image buffer, causing crashes or code execution.5h CVE-2026-1040627.8 HIG

—

———Scribus before 1.6.7 contains a heap buffer overflow vulnerability in the PICT image loader and import plugin that allows attackers to corrupt heap memory by supplying an unchecked bytesPerLine value. Attackers can craft a PICT file whose bytesPerLine exceeds the QImage scanline size, so placing or importing it crashes Scribus and may execute code as the user.5h CVE-2026-1040617.8 HIG

—

———Scribus before 1.6.7 contains a heap out-of-bounds write vulnerability in the scimgdataloader_psd loader that uses unchecked PSD file values as lookup array indexes. Attackers can convince users to place or import a crafted PSD file to corrupt heap memory, causing crashes and potentially code execution as the user.5h CVE-2026-61627—

—

———libass is a portable subtitle renderer for the `ASS`/SSA (Advanced Substation Alpha/Substation Alpha) subtitle format. Prior to 0.17.5, libass can overread and overwrite the glyph array in `wrap_lines_measure` while rendering malicious `ASS` content. In `wrap modes other than two`, a final line ending with a literal backslash-n sequence and otherwise consisting only of such sequences or spaces can remain after early trimming and make the line-measurement loops overshoot by one glyph. When the total text size exactly matches the allocated glyph-array capacity, the first loop reads an uninitialized 32-bit fixed-point `pos.x` value, although that value is not subsequently used. The second loop writes `pos.x` and `pos.y` beyond the array, zeroing the first and adding an attacker-controllable offset to the second. No actual exploitation beyond possible denial of service is known; broader exploitation is theoretical and constrained by the addresses, limited writes, and ASLR. This issue is fixed in version 0.17.5.5h