CVE-2026-84309
pypdf: Possible infinite loop for TreeObject.insert_child
pypdf is a free and open-source pure-python PDF library. Prior to 6.16.0, an attacker can craft a PDF whose cyclic tree structure causes pypdf/generic/_data_structures.py TreeObject.insert_child to follow /Next links indefinitely when a writing code path inserts a child, producing an infinite loop. This issue is fixed in version 6.16.0.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- 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: Possible infinite loop for TreeObject.insert_child
pypdf is a free and open-source pure-python PDF library. Prior to 6.16.0, an attacker can craft a PDF whose cyclic tree structure causes pypdf/generic/_data_structures.py TreeObject.insert_child to follow /Next links indefinitely when a writing code path inserts a child, producing an infinite loop. This issue is fixed in version 6.16.0.
- Record
CVE-2026-84309- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Weakness
- CWE-835
- Updated
- 2026-11-02
EUVDEUVD-2026-69477
pypdf is a free and open-source pure-python PDF library. Prior to 6.16.0, an attacker can craft a PDF whose cyclic tree structure causes pypdf/generic/_data_structures.py TreeObject.insert_child to follow /Next links indefinitely when a writing code path inserts a child, producing an infinite loop. This issue is fixed in version 6.16.0.
- Record
EUVD-2026-69477- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-jp53-mhqp-8xcg
pypdf: Possible infinite loop for TreeObject.insert_child
Impact
An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires a (usually writing) code path where TreeObject.insert_child is involved.
Patches
This has been fixed in pypdf==6.16.0.
Workarounds
If you cannot upgrade yet, consider applying the changes from PR #3964.
- Record
GHSA-jp53-mhqp-8xcg- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Weakness
- CWE-835
- Updated
- 2026-11-02
NVD
pypdf is a free and open-source pure-python PDF library. Prior to 6.16.0, an attacker can craft a PDF whose cyclic tree structure causes pypdf/generic/_data_structures.py TreeObject.insert_child to follow /Next links indefinitely when a writing code path inserts a child, producing an infinite loop. This issue is fixed in version 6.16.0.
- Record
CVE-2026-84309- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/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
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Weakness
- CWE-835
- Updated
- 2026-11-02
OSV
pypdf: Possible infinite loop for TreeObject.insert_child
pypdf is a free and open-source pure-python PDF library. Prior to 6.16.0, an attacker can craft a PDF whose cyclic tree structure causes pypdf/generic/_data_structures.py TreeObject.insert_child to follow /Next links indefinitely when a writing code path inserts a child, producing an infinite loop. This issue is fixed in version 6.16.0.
- Record
CVE-2026-84309- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Weakness
- CWE-835
- Updated
- 2026-11-04
OSVDEBIAN-CVE-2026-84309
pypdf is a free and open-source pure-python PDF library. Prior to 6.16.0, an attacker can craft a PDF whose cyclic tree structure causes pypdf/generic/_data_structures.py TreeObject.insert_child to follow /Next links indefinitely when a writing code path inserts a child, producing an infinite loop. This issue is fixed in version 6.16.0.
- Record
DEBIAN-CVE-2026-84309- CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-03
Show 6 moreShow less
OSVGHSA-jp53-mhqp-8xcg
pypdf: Possible infinite loop for TreeObject.insert_child
Impact
An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires a (usually writing) code path where TreeObject.insert_child is involved.
Patches
This has been fixed in pypdf==6.16.0.
Workarounds
If you cannot upgrade yet, consider applying the changes from PR #3964.
- Record
GHSA-jp53-mhqp-8xcg- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Weakness
- CWE-835
- Updated
- 2026-11-02
OSVPYSEC-2026-3913
pypdf: Possible infinite loop for TreeObject.insert_child
Impact
An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires a (usually writing) code path where TreeObject.insert_child is involved.
Patches
This has been fixed in pypdf==6.16.0.
Workarounds
If you cannot upgrade yet, consider applying the changes from PR #3964.
- Record
PYSEC-2026-3913- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-84309
pypdf is a free and open-source pure-python PDF library. Prior to 6.16.0, an attacker can craft a PDF whose cyclic tree structure causes pypdf/generic/_data_structures.py TreeObject.insert_child to follow /Next links indefinitely when a writing code path inserts a child, producing an infinite loop. This issue is fixed in version 6.16.0.
- Record
UBUNTU-CVE-2026-84309- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVCLSA-2026-1789369936 No score
TuxCare security update for pypdf (8 CVEs)
TuxCare rebuilt pypdf to address 8 CVEs. Fixed in 5.9.0.post17+tuxcare.
- Record
CLSA-2026-1789369936- Updated
- 2026-11-02
OSVMGASA-2026-0577 No score
Updated python-pypdf package fixes security vulnerabilities
This new version fixes several security vulnerabilities.
- Record
MGASA-2026-0577- Updated
- 2026-11-05
OSVopenSUSE-SU-2026:11726-1 No score
python313-pypdf-6.16.2-3.1 on GA media
These are all security issues fixed in the python313-pypdf-6.16.2-3.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2026:11726-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
pypdfPyPI |
before 6.16.0 | 6.16.0 |
pypdfTuxCare:PyPI From an advisory covering 7 CVEs |
5.9.0 up to 5.9.0.post17+tuxcare, plus listed versions 5.9.0.post1+tuxcare5.9.0.post10+tuxcare5.9.0.post11+tuxcare5.9.0.post12+tuxcare5.9.0.post13+tuxcare Show 11 moreShow less5.9.0.post14+tuxcare5.9.0.post15+tuxcare5.9.0.post16+tuxcare5.9.0.post2+tuxcare5.9.0.post3+tuxcare5.9.0.post4+tuxcare5.9.0.post5+tuxcare5.9.0.post6+tuxcare5.9.0.post7+tuxcare5.9.0.post8+tuxcare5.9.0.post9+tuxcare |
5.9.0.post17+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 6.19.0-1, plus listed versions 5.4.0-16.9.0-16.9.2-16.9.2-2 |
6.19.0-1 |
pypdf2Debian:12 |
All versions, plus listed versions 2.12.1-32.12.1-3+deb12u12.12.1-4 |
None known |
pypdfPyPI |
before 6.16.0, 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 |
6.16.0 |
python-pypdfMageia:10 From an advisory covering 4 CVEs |
before 6.16.2-1.mga10 | 6.16.2-1.mga10 |
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 |
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 6.16.2-3.1 | 6.16.2-3.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected | ||
| affected, aliases, references | OSV | |
| facts | OSV | |
| affected | OSV | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-84309 is a medium vulnerability (CVSS 6.9) in Py-pdf Pypdf, published September 1, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.19%, the 8th percentile. Fixed in pypdf 6.16.0.
References
github.com/py-pdf/pypdf/security/advisories/GHSA-jp53-mhqp-8xcg
Show 9 moreShow less
nvd.nist.gov/vuln/detail/CVE-2026-84309
security-tracker.debian.org/tracker/CVE-2026-84309
advisories.mageia.org/MGASA-2026-0577.html
bugs.mageia.org/show_bug.cgi?id=35672
pypi.org/project/pypdf
ubuntu.com/security/CVE-2026-84309
cve.org/CVERecord?id=CVE-2026-84309
suse.com/security/cve/CVE-2026-84309
Left out here: 63 versions. The JSON record has them.