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CVE-2026-57204

pypdf: Missing stream length values ignore defined limits

6.9 MediumFix available

pypdf is a free and open-source pure-python PDF library. Prior to 6.13.3, a maliciously crafted PDF can cause DoS. An attacker who uses this vulnerability can craft a PDF which leads to large memory usage, as MAX_DECLARED_STREAM_LENGTH is sometimes ignored. This requires parsing a content stream without a /Length value. This issue has been fixed in version 6.13.3.

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
Low

Exploit likelihood

0.37%Up 0.1 points since Jul 1, 2026
90%50%10%1%

What each source reports

CVE List Score used 6.9

pypdf: Missing stream length values ignore defined limits

pypdf is a free and open-source pure-python PDF library. Prior to 6.13.3, a maliciously crafted PDF can cause DoS. An attacker who uses this vulnerability can craft a PDF which leads to large memory usage, as MAX_DECLARED_STREAM_LENGTH is sometimes ignored. This requires parsing a content stream without a /Length value. This issue has been fixed in version 6.13.3.

Record
CVE-2026-57204
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Weakness
CWE-400
Updated
2026-11-02
EUVDEUVD-2026-40425 6.9

pypdf is a free and open-source pure-python PDF library. Prior to 6.13.3, a maliciously crafted PDF can cause DoS. An attacker who uses this vulnerability can craft a PDF which leads to large memory usage, as MAX_DECLARED_STREAM_LENGTH is sometimes ignored. This requires parsing a content stream without a /Length value. This issue has been fixed in version 6.13.3.

Record
EUVD-2026-40425
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Updated
2026-11-02
NVD 6.9

pypdf is a free and open-source pure-python PDF library. Prior to 6.13.3, a maliciously crafted PDF can cause DoS. An attacker who uses this vulnerability can craft a PDF which leads to large memory usage, as MAX_DECLARED_STREAM_LENGTH is sometimes ignored. This requires parsing a content stream without a /Length value. This issue has been fixed in version 6.13.3.

Record
CVE-2026-57204
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness
CWE-400
Updated
2026-11-02
OSV 6.9

pypdf: Missing stream length values ignore defined limits

pypdf is a free and open-source pure-python PDF library. Prior to 6.13.3, a maliciously crafted PDF can cause DoS. An attacker who uses this vulnerability can craft a PDF which leads to large memory usage, as MAX_DECLARED_STREAM_LENGTH is sometimes ignored. This requires parsing a content stream without a /Length value. This issue has been fixed in version 6.13.3.

Record
CVE-2026-57204
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Weakness
CWE-400
Updated
2026-11-04
OSVDEBIAN-CVE-2026-57204 6.5

pypdf is a free and open-source pure-python PDF library. Prior to 6.13.3, a maliciously crafted PDF can cause DoS. An attacker who uses this vulnerability can craft a PDF which leads to large memory usage, as MAX_DECLARED_STREAM_LENGTH is sometimes ignored. This requires parsing a content stream without a /Length value. This issue has been fixed in version 6.13.3.

Record
DEBIAN-CVE-2026-57204
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-03
OSVUBUNTU-CVE-2026-57204 6.9

pypdf is a free and open-source pure-python PDF library. Prior to 6.13.3, a maliciously crafted PDF can cause DoS. An attacker who uses this vulnerability can craft a PDF which leads to large memory usage, as MAX_DECLARED_STREAM_LENGTH is sometimes ignored. This requires parsing a content stream without a /Length value. This issue has been fixed in version 6.13.3.

Record
UBUNTU-CVE-2026-57204
CVSS 4.0
6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVCLSA-2026-1787843313 No score

TuxCare security update for pypdf (10 CVEs)

TuxCare rebuilt pypdf to address 10 CVEs. Fixed in 5.9.0.post16+tuxcare.

Record
CLSA-2026-1787843313
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
pypdf
TuxCare:PyPI
From an advisory covering 10 CVEs
5.9.0 up to 5.9.0.post16+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 10 moreShow less
5.9.0.post14+tuxcare5.9.0.post15+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.post16+tuxcare
pypdf
Debian: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 less
4.0.1-14.0.2-14.1.0-14.2.0-14.3.1-15.4.0-16.19.0-16.21.0-16.21.1-16.21.4-16.9.0-16.9.2-16.9.2-2
None known
pypdf
Debian: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
pypdf
Debian: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
pypdf2
Debian:12
All versions, plus listed versions
2.12.1-32.12.1-3+deb12u12.12.1-4
None known
pypdf
Ubuntu: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
pypdf
Ubuntu:25.10
All versions, plus listed versions
4.3.1-15.4.0-1
None known
pypdf
Ubuntu:26.10
All versions, plus listed versions
6.9.2-16.9.2-2
None known
pypdf
Ubuntu:26.04:LTS
All versions, plus listed versions
5.4.0-16.9.2-1
None known

History

History
RecordedChangedSources
affected
factsOSV
affectedOSV
productsNVD
first indexedCVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-57204 is a medium vulnerability (CVSS 6.9) in Py-pdf Pypdf, published June 30, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.37%, the 30th percentile. Fixed in pypdf 6.19.0-1.

References

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