CVE-2026-22690· NVD / CVE Program· CNA GitHub_M

pypdf has possible long runtimes for missing /Root object with large /Size values

Noroxi assessment

Priority: Monitor (action score 10/100)

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: 0.43% (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 6.6.0.

Low priority for now. Upgrade to py-pdf pypdf 6.6.0 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 version 6.6.0, pypdf has possible long runtimes for missing /Root object with large /Size values. An attacker who uses this vulnerability can craft a PDF which leads to possibly long runtimes for actually invalid files. This can be achieved by omitting the /Root entry in the trailer, while using a rather large /Size value. Only the non-strict reading mode is affected. This issue has been patched in version 6.6.0.

LowCVSS 2.7 · v4.0—No exploit Fix available

Published: Jan 10, 2026
Updated: Jun 17, 2026
EPSS: 0.4% · 36th percentile
CWE: CWE-400

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 10 / 40 · 2.7 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.4%

CISA SSVC decision

Exploitation: none
Automatable: yes
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · GitHub_M: 2.7; 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/E:U

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.

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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.

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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
pypdf project	pypdf	cpe:2.3:a:pypdf_project:pypdf

Affected versions

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

pypdf project pypdfbefore 6.6.0

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
- < 6.6.0affected

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 6.9.0-1	6.9.0-1
openSUSE:Tumbleweed	python-pypdf	before 6.6.0-1.1	6.6.0-1.1
PyPI	pypdf	before 6.6.0	6.6.0

Same product

pypdf project: 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-2025-62707Oct 22, 2025 · pypdf affected by possible infinite loop when reading DCT inline images without EOF marker
26Monitor
← EarlierCVE-2025-62708Oct 22, 2025 · pypdf manipulated LZWDecode streams can exhaust RAM
26Monitor
Later →CVE-2026-22691Jan 10, 2026 · pypdf has possible long runtimes for malformed startxref
10Monitor

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	6.6.0 · description	Vendor (CNA)
debian:pypdf	6.9.0-1 · Debian:14	Package registry (OSV)
opensuse:python-pypdf	6.6.0-1.1 · openSUSE:Tumbleweed	Package registry (OSV)
PyPI:pypdf	6.6.0	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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

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

CVE-2026-59936179 days apartpypdf: Possible infinite loop for not terminated inline images
34Monitor
CVE-2026-102996263 days apartpypdf: Possible large memory usage when parsing font data
34Monitor
CVE-2026-102997263 days apartpypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up)
34Monitor
CVE-2026-102998263 days apartpypdf: Possible long runtimes when generating appearance streams
34Monitor
CVE-2026-102999263 days apartpypdf: Possible long runtimes with large amount of embedded files
34Monitor
CVE-2026-103000263 days apartpypdf: Possible large memory usage when retrieving alphabetical page labels
34Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

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: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

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}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Endpoint Denial of ServiceT1499

Change log

Fix✗ → ✓Sep 28, 2026, 10:45 PM UTC

For records you follow, these changes also arrive as notifications. →

References

github.com/py-pdf/pypdf/commit/294165726b646bb7799be1cc787f593f2fdbcf45

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records