NVD / CVE Program· CNA GitHub_M

CVE-2026-57204: pypdf: Missing stream length values ignore defined limits

MediumCVSS 6.9 · v4.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 27/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.36% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
According to CISA the attack is automatable: targets can be found by mass scanning.
Fixed version: py-pdf pypdf 6.13.3.

Low priority for now. Upgrade to py-pdf pypdf 6.13.3 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published: Jun 30, 2026
Updated: Nov 2, 2026
EPSS: 0.3% · 30th percentile
CWE: CWE-400

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 27 / 40 · 6.9 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.3%

CISA SSVC decision

Exploitation: none
Automatable: yes
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · GitHub_M: 6.9; NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
py-pdf	pypdf	cpe:2.3:a:py-pdf:pypdf

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

py-pdf pypdf
- < 6.13.3affected

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

py-pdf pypdfbefore 6.13.3

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:12	pypdf	from 0	—
Debian:12	pypdf2	from 0	—
Debian:14	pypdf	before 6.19.0-1	6.19.0-1
PyPI	pypdf	before 6.13.3	6.13.3

Same product

py-pdf: all records

Other highest-scoring records for the same primary product.

CVE-2026-103000pypdf: Possible large memory usage when retrieving alphabetical page labels
34Monitor
CVE-2026-102999pypdf: Possible long runtimes with large amount of embedded files
34Monitor
CVE-2026-102998pypdf: Possible long runtimes when generating appearance streams
34Monitor

Published before and after this one in the same product

← EarlierCVE-2026-54531Jun 22, 2026 · pypdf: Possible infinite loop when processing outlines/bookmarks in writer
27Monitor
← EarlierCVE-2026-54651Jun 22, 2026 · pypdf: Possible infinite loop when processing threads/articles in writer
27Monitor
Later →CVE-2026-59937Jul 8, 2026 · pypdf: Possible long runtimes for repeated malformed cross-reference entries
27Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
py-pdf pypdf	6.13.3 · description	Vendor (CNA)
debian:pypdf	6.19.0-1 · Debian:14	Package registry (OSV)
PyPI:pypdf	6.13.3	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

CVE-2026-599368 days apartpypdf: Possible infinite loop for not terminated inline images
34Monitor
CVE-2026-10299392 days apartpypdf: Possible large memory usage when retrieving Roman page labels
34Monitor
CVE-2026-10299492 days apartpypdf: Possible long runtimes/large memory usage when parsing indirect objects
34Monitor
CVE-2026-10299792 days apartpypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up)
34Monitor
CVE-2026-10299892 days apartpypdf: Possible long runtimes when generating appearance streams
34Monitor
CVE-2026-10299992 days apartpypdf: Possible long runtimes with large amount of embedded files
34Monitor

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · public bounty program.

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: X

Weakness class (CWE)

CWE-400 · Uncontrolled Resource Consumption

CVSS vector

CVSS: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

nvd-secondary

Root cause

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

The bug in code

The whole CWE-400 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1function expand(node) {
2  return node.children.map(expand);
3}

Fixed

1const MAX_DEPTH = 32;
2function expand(node, depth = 0) {
3  if (depth > MAX_DEPTH) throw new Error("too deep");
4  return node.children.map((c) => expand(c, depth + 1));
5}