CVE-2025-55197
pypdf's Manipulated FlateDecode streams can exhaust RAM
pypdf is a free and open-source pure-python PDF library. Prior to version 6.0.0, an attacker can craft a PDF which leads to the RAM being exhausted. This requires just reading the file if a series of FlateDecode filters is used on a malicious cross-reference stream. Other content streams are affected on explicit access. This issue has been fixed in 6.0.0. If an update is not possible, a workaround involves including the fixed code from pypdf.filters.decompress into the existing filters file.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
pypdf's Manipulated FlateDecode streams can exhaust RAM
pypdf is a free and open-source pure-python PDF library. Prior to version 6.0.0, an attacker can craft a PDF which leads to the RAM being exhausted. This requires just reading the file if a series of FlateDecode filters is used on a malicious cross-reference stream. Other content streams are affected on explicit access. This issue has been fixed in 6.0.0. If an update is not possible, a workaround involves including the fixed code from pypdf.filters.decompress into the existing filters file.
- Record
CVE-2025-55197- CVSS 4.0
- 6.6 Medium
CVSS: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 - Weakness
- CWE-400, CWE-770
- Updated
- 2026-11-02
EUVDEUVD-2025-24648
pypdf is a free and open-source pure-python PDF library. Prior to version 6.0.0, an attacker can craft a PDF which leads to the RAM being exhausted. This requires just reading the file if a series of FlateDecode filters is used on a malicious cross-reference stream. Other content streams are affected on explicit access. This issue has been fixed in 6.0.0. If an update is not possible, a workaround involves including the fixed code from pypdf.filters.decompress into the existing filters file.
- Record
EUVD-2025-24648- CVSS 4.0
- 6.6 Medium
CVSS: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 - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-7hfw-26vp-jp8m
PyPDF's Manipulated FlateDecode streams can exhaust RAM
Impact
An attacker who uses this vulnerability can craft a PDF which leads to the RAM being exhausted. This requires just reading the file if a series of FlateDecode filters is used on a malicious cross-reference stream. Other content streams are affected on explicit access.
Patches
This has been fixed in pypdf==6.0.0.
Workarounds
If you cannot upgrade yet, you might want to implement the workaround for pypdf.filters.decompress yourself: https://github.com/py-pdf/pypdf/blob/0dd57738bbdcdb63f0fb43d8a6b3d222b6946595/pypdf/filters.py#L72-L143
References
This issue has been reported in #3429 and fixed in #3430.
- Record
GHSA-7hfw-26vp-jp8m- CVSS 4.0
- 6.6 Medium
CVSS: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 - Weakness
- CWE-400, CWE-770
- Updated
- 2026-11-02
NVD
pypdf is a free and open-source pure-python PDF library. Prior to version 6.0.0, an attacker can craft a PDF which leads to the RAM being exhausted. This requires just reading the file if a series of FlateDecode filters is used on a malicious cross-reference stream. Other content streams are affected on explicit access. This issue has been fixed in 6.0.0. If an update is not possible, a workaround involves including the fixed code from pypdf.filters.decompress into the existing filters file.
- Record
CVE-2025-55197- CVSS 4.0
- 6.6 Medium
CVSS: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 - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400, CWE-770
- Updated
- 2026-11-02
OSV
pypdf's Manipulated FlateDecode streams can exhaust RAM
pypdf is a free and open-source pure-python PDF library. Prior to version 6.0.0, an attacker can craft a PDF which leads to the RAM being exhausted. This requires just reading the file if a series of FlateDecode filters is used on a malicious cross-reference stream. Other content streams are affected on explicit access. This issue has been fixed in 6.0.0. If an update is not possible, a workaround involves including the fixed code from pypdf.filters.decompress into the existing filters file.
- Record
CVE-2025-55197- CVSS 4.0
- 6.6 Medium
CVSS: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 - Weakness
- CWE-400, CWE-770
- Updated
- 2026-11-04
OSVDEBIAN-CVE-2025-55197
pypdf is a free and open-source pure-python PDF library. Prior to version 6.0.0, an attacker can craft a PDF which leads to the RAM being exhausted. This requires just reading the file if a series of FlateDecode filters is used on a malicious cross-reference stream. Other content streams are affected on explicit access. This issue has been fixed in 6.0.0. If an update is not possible, a workaround involves including the fixed code from pypdf.filters.decompress into the existing filters file.
- Record
DEBIAN-CVE-2025-55197- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-03
Show 7 moreShow less
OSVGHSA-7hfw-26vp-jp8m
PyPDF's Manipulated FlateDecode streams can exhaust RAM
Impact
An attacker who uses this vulnerability can craft a PDF which leads to the RAM being exhausted. This requires just reading the file if a series of FlateDecode filters is used on a malicious cross-reference stream. Other content streams are affected on explicit access.
Patches
This has been fixed in pypdf==6.0.0.
Workarounds
If you cannot upgrade yet, you might want to implement the workaround for pypdf.filters.decompress yourself: https://github.com/py-pdf/pypdf/blob/0dd57738bbdcdb63f0fb43d8a6b3d222b6946595/pypdf/filters.py#L72-L143
References
This issue has been reported in #3429 and fixed in #3430.
- Record
GHSA-7hfw-26vp-jp8m- CVSS 4.0
- 6.6 Medium
CVSS: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 - Weakness
- CWE-400, CWE-770
- Updated
- 2026-11-02
OSVPYSEC-2026-1830
PyPDF's Manipulated FlateDecode streams can exhaust RAM
Impact
An attacker who uses this vulnerability can craft a PDF which leads to the RAM being exhausted. This requires just reading the file if a series of FlateDecode filters is used on a malicious cross-reference stream. Other content streams are affected on explicit access.
Patches
This has been fixed in pypdf==6.0.0.
Workarounds
If you cannot upgrade yet, you might want to implement the workaround for pypdf.filters.decompress yourself: https://github.com/py-pdf/pypdf/blob/0dd57738bbdcdb63f0fb43d8a6b3d222b6946595/pypdf/filters.py#L72-L143
References
This issue has been reported in #3429 and fixed in #3430.
- Record
PYSEC-2026-1830- CVSS 4.0
- 6.6 Medium
CVSS: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 - Updated
- 2026-11-02
OSVUBUNTU-CVE-2025-55197
pypdf is a free and open-source pure-python PDF library. Prior to version 6.0.0, an attacker can craft a PDF which leads to the RAM being exhausted. This requires just reading the file if a series of FlateDecode filters is used on a malicious cross-reference stream. Other content streams are affected on explicit access. This issue has been fixed in 6.0.0. If an update is not possible, a workaround involves including the fixed code from pypdf.filters.decompress into the existing filters file.
- Record
UBUNTU-CVE-2025-55197- CVSS 4.0
- 6.6 Medium
CVSS: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 - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVCLSA-2025-1759968741 No score
TuxCare security update for pypdf (1 CVE)
TuxCare rebuilt pypdf to address 1 CVE. Fixed in 5.9.0.post1+tuxcare.
- Record
CLSA-2025-1759968741- Updated
- 2026-11-02
OSVopenSUSE-SU-2025:15439-1 No score
python311-pypdf-6.0.0-1.1 on GA media
These are all security issues fixed in the python311-pypdf-6.0.0-1.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2025:15439-1- Updated
- 2026-11-02
OSVopenSUSE-SU-2026:10238-1 No score
python311-PyPDF2-2.11.1-4.1 on GA media
These are all security issues fixed in the python311-PyPDF2-2.11.1-4.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2026:10238-1- Updated
- 2026-11-02
OSVopenSUSE-SU-2026:20333-1 No score
Security update for python-PyPDF2
This update for python-PyPDF2 fixes the following issues:
Changes in python-PyPDF2:
-
CVE-2026-27628: Fixed infinite loop when loading circular /Prev entries in cross-reference streams (bsc#1258940)
-
CVE-2026-27888: Fixed issue where manipulated FlateDecode XFA streams can exhaust RAM (bsc#1258934)
-
CVE-2025-55197: Fixed denial of service via craft PDF (bsc#1248089)
-
CVE-2026-27024: Fixed infinite loop when processing TreeObject (bsc#1258691)
-
CVE-2026-27025: Fixed long runtimes/large memory usage for large /ToUnicode streams (bsc#1258692)
-
CVE-2026-27026: Fixed long runtimes for malformed FlateDecode streams (bsc#1258693)
-
Convert to pip-based build
- Record
openSUSE-SU-2026:20333-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
pypdfPyPI |
before 6.0.0 | 6.0.0 |
pypdfTuxCare:PyPI |
5.9.0 up to 5.9.0.post1+tuxcare | 5.9.0.post1+tuxcare |
pypdfDebian:12 |
All versions, plus listed versions 3.17.4-13.4.1-13.4.1-1+deb12u14.0.0-14.0.0-1~exp1 Show 13 moreShow less4.0.1-14.0.2-14.1.0-14.2.0-14.3.1-15.4.0-16.19.0-16.21.0-16.21.1-16.21.4-16.9.0-16.9.2-16.9.2-2 |
None known |
pypdfDebian:13 |
All versions, plus listed versions 5.4.0-16.19.0-16.21.0-16.21.1-16.21.4-16.9.0-16.9.2-16.9.2-2 |
None known |
pypdfDebian:14 |
before 6.9.0-1, plus listed versions 5.4.0-1 |
6.9.0-1 |
pypdf2Debian:12 |
All versions, plus listed versions 2.12.1-32.12.1-3+deb12u12.12.1-4 |
None known |
pypdfPyPI |
before 6.0.0, plus listed versions 1.01.11.101.111.12 Show 45 moreShow less1.131.21.31.41.51.61.71.81.93.1.03.10.03.11.03.11.13.12.03.12.13.12.23.13.03.14.03.15.03.15.13.15.23.15.33.15.43.15.53.16.03.16.13.16.23.16.33.16.43.17.03.17.13.17.23.17.33.17.43.2.03.2.13.3.03.4.03.4.13.5.03.5.13.5.23.6.03.7.03.7.1 |
6.0.0 |
pypdf2Ubuntu:Pro:16.04:LTS |
All versions, plus listed versions 1.23+git20141008-11.25.1-11.25.1-1ubuntu0.1~esm11.25.1-1ubuntu0.1~esm2 |
None known |
pypdf2Ubuntu:Pro:18.04:LTS |
All versions, plus listed versions 1.26.0-21.26.0-2ubuntu0.1~esm11.26.0-2ubuntu0.1~esm2 |
None known |
pypdf2Ubuntu:20.04:LTS |
All versions, plus listed versions 1.26.0-21.26.0-3ubuntu11.26.0-3ubuntu1.20.04.11.26.0-3ubuntu1.20.04.2 |
None known |
Show 8 moreShow less
| Package | Affected | Fixed |
|---|---|---|
pypdf2Ubuntu:22.04:LTS |
All versions, plus listed versions 1.26.0-41.26.0-4ubuntu0.22.04.11.26.0-4ubuntu0.22.04.2 |
None known |
pypdfUbuntu:24.04:LTS |
All versions, plus listed versions 3.4.1-13.17.4-14.0.0-14.0.1-14.0.2-1 |
None known |
pypdf2Ubuntu:24.04:LTS |
All versions, plus listed versions 2.12.1-32.12.1-4 |
None known |
pypdfUbuntu:25.10 |
All versions, plus listed versions 4.3.1-15.4.0-1 |
None known |
pypdfUbuntu:26.10 |
All versions, plus listed versions 6.9.2-16.9.2-2 |
None known |
pypdfUbuntu:26.04:LTS |
All versions, plus listed versions 5.4.0-16.9.2-1 |
None known |
python-pypdfopenSUSE:Tumbleweed |
before 6.0.0-1.1 | 6.0.0-1.1 |
python-PyPDF2openSUSE:Tumbleweed From an advisory covering 4 CVEs |
before 2.11.1-4.1 | 2.11.1-4.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected | ||
| facts | OSV | |
| affected | OSV | |
| affected | ||
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-55197 is a medium vulnerability (CVSS 6.6) in Py-pdf Pypdf, published August 13, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.51%, the 43rd percentile. Fixed in pypdf 6.0.0.
References
github.com/py-pdf/pypdf/security/advisories/GHSA-7hfw-26vp-jp8m
nvd.nist.gov/vuln/detail/CVE-2025-55197
Show 19 moreShow less
security-tracker.debian.org/tracker/CVE-2025-55197
pypi.org/project/pypdf
ubuntu.com/security/CVE-2025-55197
cve.org/CVERecord?id=CVE-2025-55197
suse.com/security/cve/CVE-2025-55197
bugzilla.suse.com/1248089
Left out here: 24 versions. The JSON record has them.