CVE-2026-77220
PDFio < 1.6.5 Dangling Pointer via Dictionary String-Formatting
PDFio before 1.6.5 contains a dangling pointer vulnerability in the dictionary string-formatting function that stores a pointer to a stack-local buffer in the document dictionary without copying the string value. In multi-threaded or pooled-request environments, attackers or concurrent users can trigger stack memory reuse across requests, causing cross-tenant document content corruption by silently overwriting one caller's dictionary string values with another caller's data.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
7.1
PDFio < 1.6.5 Dangling Pointer via Dictionary String-Formatting
PDFio before 1.6.5 contains a dangling pointer vulnerability in the dictionary string-formatting function that stores a pointer to a stack-local buffer in the document dictionary without copying the string value. In multi-threaded or pooled-request environments, attackers or concurrent users can trigger stack memory reuse across requests, causing cross-tenant document content corruption by silently overwriting one caller's dictionary string values with another caller's data.
- Record
CVE-2026-77220- CVSS 4.0
- 7.1 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-825
- Updated
- 2026-11-02
EUVDEUVD-2026-64163
7.1
PDFio before 1.6.5 contains a dangling pointer vulnerability in the dictionary string-formatting function that stores a pointer to a stack-local buffer in the document dictionary without copying the string value. In multi-threaded or pooled-request environments, attackers or concurrent users can trigger stack memory reuse across requests, causing cross-tenant document content corruption by silently overwriting one caller's dictionary string values with another caller's data.
- Record
EUVD-2026-64163- CVSS 4.0
- 7.1 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-2fr4-jfvm-chmp
7.1
PDFio before 1.6.5 contains a dangling pointer vulnerability in the dictionary string-formatting...
PDFio before 1.6.5 contains a dangling pointer vulnerability in the dictionary string-formatting function that stores a pointer to a stack-local buffer in the document dictionary without copying the string value. In multi-threaded or pooled-request environments, attackers or concurrent users can trigger stack memory reuse across requests, causing cross-tenant document content corruption by silently overwriting one caller's dictionary string values with another caller's data.
- Record
GHSA-2fr4-jfvm-chmp- CVSS 4.0
- 7.1 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/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 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-825
- Updated
- 2026-11-02
NVD
7.1
PDFio before 1.6.5 contains a dangling pointer vulnerability in the dictionary string-formatting function that stores a pointer to a stack-local buffer in the document dictionary without copying the string value. In multi-threaded or pooled-request environments, attackers or concurrent users can trigger stack memory reuse across requests, causing cross-tenant document content corruption by silently overwriting one caller's dictionary string values with another caller's data.
- Record
CVE-2026-77220- CVSS 4.0
- 7.1 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/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 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-825
- Updated
- 2026-11-02
OSV
7.1
PDFio < 1.6.5 Dangling Pointer via Dictionary String-Formatting
PDFio before 1.6.5 contains a dangling pointer vulnerability in the dictionary string-formatting function that stores a pointer to a stack-local buffer in the document dictionary without copying the string value. In multi-threaded or pooled-request environments, attackers or concurrent users can trigger stack memory reuse across requests, causing cross-tenant document content corruption by silently overwriting one caller's dictionary string values with another caller's data.
- Record
CVE-2026-77220- CVSS 4.0
- 7.1 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-825
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-77220
7.1
PDFio before 1.6.5 contains a dangling pointer vulnerability in the dictionary string-formatting function that stores a pointer to a stack-local buffer in the document dictionary without copying the string value. In multi-threaded or pooled-request environments, attackers or concurrent users can trigger stack memory reuse across requests, causing cross-tenant document content corruption by silently overwriting one caller's dictionary string values with another caller's data.
- Record
DEBIAN-CVE-2026-77220- CVSS 4.0
- 7.1 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/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 - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-77220
7.1
PDFio before 1.6.5 contains a dangling pointer vulnerability in the dictionary string-formatting function that stores a pointer to a stack-local buffer in the document dictionary without copying the string value. In multi-threaded or pooled-request environments, attackers or concurrent users can trigger stack memory reuse across requests, causing cross-tenant document content corruption by silently overwriting one caller's dictionary string values with another caller's data.
- Record
UBUNTU-CVE-2026-77220- CVSS 4.0
- 7.1 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
ippsampleDebian:12 |
All versions, plus listed versions 0.0.0~git20220215.f365352-10.0.0~git20220215.f365352-20.0~git20220607.72f89b3-1 |
None known |
ippsampleDebian:14 |
All versions, plus listed versions 0.0.0~git20220215.f365352-10.0.0~git20220215.f365352-20.0~git20210916.53e4740-10.0~git20210916.53e4740-20.0~git20211022.c75af30-10.0~git20211022.c75af30-20.0~git20220215.f365352-10.0~git20220607.72f89b3-1 |
None known |
pdfioDebian:14 |
before 1.6.5+dfsg-1, plus listed versions 1.5.1+dfsg-11.6.1+dfsg-11.6.1+dfsg-21.6.1+dfsg-31.6.2+dfsg-11.6.3+dfsg-11.6.3+dfsg-2 |
1.6.5+dfsg-1 |
ippsampleUbuntu:18.04:LTS |
All versions, plus listed versions 0.0+20180213-0ubuntu1 |
None known |
ippsampleUbuntu:20.04:LTS |
All versions, plus listed versions 0.0+20180213-0ubuntu1 |
None known |
ippsampleUbuntu:22.04:LTS |
All versions, plus listed versions 0.0+20180213-0ubuntu1 |
None known |
ippsampleUbuntu:24.04:LTS |
All versions, plus listed versions 0.0+20180213-0ubuntu10.0+20180213-0ubuntu20.0+20180213-0ubuntu3 |
None known |
ippsampleUbuntu:26.10 |
All versions, plus listed versions 0.0.0~git20220215.f365352-1build10.0.0~git20220215.f365352-2 |
None known |
ippsampleUbuntu:26.04:LTS |
All versions, plus listed versions 0.0+20180213-0ubuntu30.0.0~git20220215.f365352-10.0.0~git20220215.f365352-1build1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-77220 is a high vulnerability (CVSS 7.1) in Michaelrsweet Pdfio, published August 21, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.42%, the 36th percentile. Fixed in pdfio 1.6.5+dfsg-1.
References
github.com/michaelrsweet/pdfio/releases/tag/v1.6.5
github.com/michaelrsweet/pdfio/commit/22b9afc800c5833f9e851e35938972bd4c76a357
vulncheck.com/advisories/pdfio-dangling-pointer-via-dictionary-string-formatting
nvd.nist.gov/vuln/detail/CVE-2026-77220
github.com/advisories/GHSA-2fr4-jfvm-chmp
github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77220.json