CVE-2026-27026— pypdf possibly has long runtimes for malformed FlateDecode streams
Quick assessment
Affected
py-pdf pypdf
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
pypdf是py-pdf开源的一个免费开源的纯 python PDF 库。能够拆分、合并、裁剪和转换 PDF 文件的页面。 pypdf 6.7.1之前版本存在安全漏洞，该漏洞源于处理格式错误的/FlateDecode流，可能导致长时间运行。
Possible ATT&CK Techniques 1 AI
T1496 · Resource Hijacking
Get alerts for future matching vulnerabilities
Log in to subscribe
I. Basic Information for CVE-2026-27026
Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗
Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.
Vulnerability Title
pypdf possibly has long runtimes for malformed FlateDecode streams
Source: CVE Program / CVE List V5
Vulnerability Description
pypdf is a free and open-source pure-python PDF library. Prior to 6.7.1, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires a malformed /FlateDecode stream, where the byte-by-byte decompression is used. This vulnerability is fixed in 6.7.1.
Source: CVE Program / CVE List V5
CVSS Information
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
Source: CVE Program / CVE List V5
Vulnerability Type
不加限制或调节的资源分配
Source: CVE Program / CVE List V5
Vulnerability Title
pypdf 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
pypdf是py-pdf开源的一个免费开源的纯 python PDF 库。能够拆分、合并、裁剪和转换 PDF 文件的页面。 pypdf 6.7.1之前版本存在安全漏洞，该漏洞源于处理格式错误的/FlateDecode流，可能导致长时间运行。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
II. Public POCs for CVE-2026-27026
| # | POC Description | Source Link | Shenlong Link |
|---|
AI-Generated POC
Premium
No public POC found.
Login to generate AI POCIII. Intelligence Information for CVE-2026-27026
请登录查看更多情报信息。
Same Patch Batch · py-pdf · 2026-02-20 · 3 CVEs total
| CVE-2026-27024 | pypdf has a possible infinite loop when processing TreeObject | |
| CVE-2026-27025 | pypdf has possible long runtimes/large memory usage for large /ToUnicode streams |
IV. Related Vulnerabilities
Same product: pypdf
-
CVE-2026-103000
pypdf: Possible large memory usage when retrieving alphabeti -
CVE-2026-102999
pypdf: Possible long runtimes with large amount of embedded -
CVE-2026-102998
pypdf: Possible long runtimes when generating appearance str -
CVE-2026-102997
pypdf: Possible long runtimes for partially malformed FlateD -
CVE-2026-102996
pypdf: Possible large memory usage when parsing font data
Same vendor: py-pdf
-
CVE-2026-103000
pypdf: Possible large memory usage when retrieving alphabeti -
CVE-2026-102999
pypdf: Possible long runtimes with large amount of embedded -
CVE-2026-102998
pypdf: Possible long runtimes when generating appearance str -
CVE-2026-102997
pypdf: Possible long runtimes for partially malformed FlateD -
CVE-2026-102996
pypdf: Possible large memory usage when parsing font data
Same weakness: CWE-770
-
CVE-2026-97873
Legacy PBES1 and PKCS#12 PBE iteration count honoured unboun -
CVE-2026-104845
Seroval: Memory exhaustion via unchecked TypedArray length i -
CVE-2026-66054
Apache Thrift: C++ THeaderTransport does not enforce configu -
CVE-2026-61374
Apache Thrift: Java TSaslTransport post-auth data-frame miss -
CVE-2026-63772
Apache Thrift: Unauthenticated single-packet crash of Go Thr
V. Comments for CVE-2026-27026
No comments yet