Pillow has a PDF Parsing Trailer Infinite Loop (DoS)

ImpactAn attacker can supply a malicious PDF that causes the process to hang indefinitely, consuming 100% CPU and making the application unresponsive. PatchesPatched version: 12.2.0.PdfParser introduced in Pillow 4.2.0 follows Prev pointers in PDF trailers to read cross-reference sections. If...

pypdf: Possible infinite loop during recovery attempts in DictionaryObject.read_from_stream

ImpactAn attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires reading a file in non-strict mode. PatchesThis has been fixed in pypdf==6.9.2. WorkaroundsIf users cannot upgrade yet, consider applying the changes from PR 3693...

PYSEC-2026-3012 pypdf: Possible infinite loop during recovery attempts in DictionaryObject.read_from_stream

Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires reading a file in non-strict mode. Patches This has been fixed in pypdf==6.9.2. Workarounds If users cannot upgrade yet, consider applying the changes from PR 3693...

pypdf has a possible infinite loop when loading circular /Prev entries in cross-reference streams

ImpactAn attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires reading the file. PatchesThis has been fixed in pypdf==6.7.2. WorkaroundsIf users cannot upgrade yet, consider applying the changes from PR 3655...

PYSEC-2026-3005 pypdf has a possible infinite loop when loading circular /Prev entries in cross-reference streams

Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires reading the file. Patches This has been fixed in pypdf==6.7.2. Workarounds If users cannot upgrade yet, consider applying the changes from PR 3655...

pypdf has a possible infinite loop when processing TreeObject

ImpactAn attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires accessing the children of a TreeObject, for example as part of outlines. PatchesThis has been fixed in pypdf==6.7.1. WorkaroundsIf you cannot upgrade yet, consider applying the changes fro...

PYSEC-2026-3013 pypdf has a possible infinite loop when processing TreeObject

Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires accessing the children of a TreeObject, for example as part of outlines. Patches This has been fixed in pypdf==6.7.1. Workarounds If you cannot upgrade yet, consider applying the changes...

PYSEC-2026-3008 pypdf and PyPDF2 possible Infinite Loop when a comment isn't followed by a character

Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop if parsecontentstream is executed. This infinite loop blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage. That is, for example, the case if the...

pypdf and PyPDF2 possible Infinite Loop when a comment isn't followed by a character

ImpactAn attacker who uses this vulnerability can craft a PDF which leads to an infinite loop if parsecontentstream is executed. This infinite loop blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage. That is, for example, the case if the...

PT-2026-59635

Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires accessing the children of a TreeObject, for example as part of outlines. Patches This has been fixed in pypdf==6.7.1. Workarounds If you cannot upgrade yet, consider applying the changes...

PT-2026-59657

Impact Given a malformed % case % tag without associated % when % or % else % block, and no terminating % endcase % tag, Python Liquid hangs in an infinite loop at parse time. This allows malicious template authors to craft templates for a denial of service attack. Patches The issue is fixed in...

PT-2026-59640

Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires merging a file with threads/articles into a writer. Patches This has been fixed in pypdf==6.13.1. Workarounds If users cannot upgrade yet, consider applying the changes from PR 3839...

PT-2026-59634

Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires reading a file in non-strict mode. Patches This has been fixed in pypdf==6.9.2. Workarounds If users cannot upgrade yet, consider applying the changes from PR 3693...

PT-2026-59699

In OpenStack Swift before 2.36.2 and 2.37.2, s3api middleware enters an infinite loop when processing a truncated aws-chunked PUT request body. The StreamingInput class repeatedly appends an empty buffer and re-reads, causing the proxy-server worker handling the request to become permanently...

PT-2026-59184

In OpenStack Ironic through 35.x before a3f6d73, during image handling, an infinite loop in checksum calculations can occur via the file:///dev/zero URL...

PT-2026-59644

Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires merging a file with outlines into a writer. Patches This has been fixed in pypdf==6.13.0. Workarounds If you cannot upgrade yet, consider applying the changes from PR 3830...

PT-2026-59631

Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires extracting the text in layout mode. Patches This has been fixed in pypdf==6.13.0. Workarounds If you cannot upgrade yet, consider applying the changes from PR 3830...

PT-2026-59627

Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires reading the file. Patches This has been fixed in pypdf==6.7.2. Workarounds If users cannot upgrade yet, consider applying the changes from PR 3655...

PT-2026-59630

Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop if parse content stream is executed. This infinite loop blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage. That is, for example, the case if th...

Uncontrolled Resource Consumption (Infinite Loop)

pypdf is vulnerable to Uncontrolled Resource Consumption Infinite Loop. The vulnerability is due to improper handling of crafted PDF files containing threads/articles during the merge operation, which allows an attacker to trigger an infinite loop by supplying a malicious PDF, resulting in a...