CVE-2025-66019
published 2025-11-26CVE-2025-66019: pypdf is a free and open-source pure-python PDF library. Prior to version 6.4.0, an attacker who uses this vulnerability can craft a PDF which leads to a…
PriorityP340medium6.6CVSS 4.0
AVNACLATNPRNUINVCNVINVAHSCNSINSANEUCRXIRXARXMAVXMACXMATXMPRXMUIXMVCXMVIXMVAXMSCXMSIXMSAXSXAUXRXVXREXUX
EPSS
0.31%
23.0th percentile
pypdf is a free and open-source pure-python PDF library. Prior to version 6.4.0, an attacker who uses this vulnerability can craft a PDF which leads to a memory usage of up to 1 GB per stream. This requires parsing the content stream of a page using the LZWDecode filter. This issue has been patched in version 6.4.0.
Affected
3 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | pypdf | — | — |
| py-pdf | pypdf | < 6.4.0 | 6.4.0 |
| pypdf_project | pypdf | >= 0 < 6.4.0 | 6.4.0 |
CVSS provenance
nvdv4.06.6MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
osv6.6MEDIUM
vendor_debian6.6LOW
vendor_redhat6.6MEDIUM
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Red Hat
pypdf: pypdf manipulated LZWDecode streams can exhaust RAM
vendor_redhat·2025-11-25·CVSS 6.6
CVE-2025-66019 [MEDIUM] CWE-770 pypdf: pypdf manipulated LZWDecode streams can exhaust RAM
pypdf: pypdf manipulated LZWDecode streams can exhaust RAM
pypdf is a free and open-source pure-python PDF library. Prior to version 6.4.0, an attacker who uses this vulnerability can craft a PDF which leads to a memory usage of up to 1 GB per stream. This requires parsing the content stream of a page using the LZWDecode filter. This issue has been patched in version 6.4.0.
A resource exhaustion flaw has been discovered in pypdf. An attacker who uses this vulnerability can craft a PDF which leads to a memory usage of up to 1 GB per stream. This requires parsing the content stream of a page using the LZWDecode filter.
Mitigation: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use an
Debian
CVE-2025-66019: pypdf - pypdf is a free and open-source pure-python PDF library. Prior to version 6.4.0,...
vendor_debian·2025·CVSS 6.6
CVE-2025-66019 [MEDIUM] CVE-2025-66019: pypdf - pypdf is a free and open-source pure-python PDF library. Prior to version 6.4.0,...
pypdf is a free and open-source pure-python PDF library. Prior to version 6.4.0, an attacker who uses this vulnerability can craft a PDF which leads to a memory usage of up to 1 GB per stream. This requires parsing the content stream of a page using the LZWDecode filter. This issue has been patched in version 6.4.0.
Scope: local
bookworm: resolved
forky: resolved
sid: resolved
trixie: resolved
OSV
CVE-2025-66019: pypdf is a free and open-source pure-python PDF library
osv·2025-11-26·CVSS 6.6
CVE-2025-66019 [MEDIUM] CVE-2025-66019: pypdf is a free and open-source pure-python PDF library
pypdf is a free and open-source pure-python PDF library. Prior to version 6.4.0, an attacker who uses this vulnerability can craft a PDF which leads to a memory usage of up to 1 GB per stream. This requires parsing the content stream of a page using the LZWDecode filter. This issue has been patched in version 6.4.0.
OSV
pypdf's LZWDecode streams be manipulated to exhaust RAM
osv·2025-11-24
CVE-2025-66019 [MEDIUM] pypdf's LZWDecode streams be manipulated to exhaust RAM
pypdf's LZWDecode streams be manipulated to exhaust RAM
### Impact
An attacker who uses this vulnerability can craft a PDF which leads to a memory usage of up to 1 GB per stream. This requires parsing the content stream of a page using the LZWDecode filter.
This is a follow up to [GHSA-jfx9-29x2-rv3j](https://github.com/py-pdf/pypdf/security/advisories/GHSA-jfx9-29x2-rv3j) to align the default limit with the one for *zlib*.
### Patches
This has been fixed in [pypdf==6.4.0](https://github.com/py-pdf/pypdf/releases/tag/6.4.0).
### Workarounds
If users cannot upgrade yet, use the line below to overwrite the default in their code:
```python
pypdf.filters.LZW_MAX_OUTPUT_LENGTH = 75_000_000
```
GHSA
pypdf's LZWDecode streams be manipulated to exhaust RAM
ghsa·2025-11-24
CVE-2025-66019 [MEDIUM] CWE-400 pypdf's LZWDecode streams be manipulated to exhaust RAM
pypdf's LZWDecode streams be manipulated to exhaust RAM
### Impact
An attacker who uses this vulnerability can craft a PDF which leads to a memory usage of up to 1 GB per stream. This requires parsing the content stream of a page using the LZWDecode filter.
This is a follow up to [GHSA-jfx9-29x2-rv3j](https://github.com/py-pdf/pypdf/security/advisories/GHSA-jfx9-29x2-rv3j) to align the default limit with the one for *zlib*.
### Patches
This has been fixed in [pypdf==6.4.0](https://github.com/py-pdf/pypdf/releases/tag/6.4.0).
### Workarounds
If users cannot upgrade yet, use the line below to overwrite the default in their code:
```python
pypdf.filters.LZW_MAX_OUTPUT_LENGTH = 75_000_000
```
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
2025-11-26
Published