palletsprojects vulnerabilities

Products

• werkzeug 13
• jinja 8
• flask 4
• quart 1

Latest palletsprojects CVEs

Newest publication first

1. CVE-2026-27205 Flask session does not add `Vary: Cookie` header when accessed in some ways

   Published 2026-02-21

   Low·CVSS 2.3 EPSS 0.40%

   Flask is a web server gateway interface (WSGI) web application framework. In versions 3.1.2 and below, when the session object is accessed, Flask should set the Vary: Cookie header., resulting in a Use of Cache Containing Sensitive Information vulnerability. The logic instructs c...

2. CVE-2026-27199 Werkzeug safe_join() allows Windows special device names

   Published 2026-02-21

   Medium·CVSS 6.3 EPSS 0.63%

   Werkzeug is a comprehensive WSGI web application library. Versions 3.1.5 and below, the safe_join function allows Windows device names as filenames if preceded by other path segments. This was previously reported as GHSA-hgf8-39gv-g3f2, but the added filtering failed to account f...

3. CVE-2026-21860 Werkzeug safe_join() allows Windows special device names with compound extensions

   Published 2026-01-08

   Medium·CVSS 6.3 EPSS 0.48%

   Werkzeug is a comprehensive WSGI web application library. Prior to version 3.1.5, Werkzeug's safe_join function allows path segments with Windows device names that have file extensions or trailing spaces. On Windows, there are special device names such as CON, AUX, etc that are i...

4. CVE-2025-66221 Werkzeug safe_join() allows Windows special device names

   Published 2025-11-29

   Medium·CVSS 6.3 EPSS 0.55%

   Werkzeug is a comprehensive WSGI web application library. Prior to version 3.1.4, Werkzeug's safe_join function allows path segments with Windows device names. On Windows, there are special device names such as CON, AUX, etc that are implicitly present and readable in every direc...

5. CVE-2025-27516 Jinja sandbox breakout through attr filter selecting format method

   Published 2025-03-05

   Medium·CVSS 5.4 EPSS 0.51%

   Jinja is an extensible templating engine. Prior to 3.1.6, an oversight in how the Jinja sandboxed environment interacts with the |attr filter allows an attacker that controls the content of a template to execute arbitrary Python code. To exploit the vulnerability, an attacker nee...

6. CVE-2024-56326 Jinja has a sandbox breakout through indirect reference to format method

   Published 2024-12-23

   Medium·CVSS 5.4 EPSS 0.52%

   Jinja is an extensible templating engine. Prior to 3.1.5, An oversight in how the Jinja sandboxed environment detects calls to str.format allows an attacker that controls the content of a template to execute arbitrary Python code. To exploit the vulnerability, an attacker needs t...

7. CVE-2024-56201 Jinja has a sandbox breakout through malicious filenames

   Published 2024-12-23

   Medium·CVSS 5.4 EPSS 0.31%

   Jinja is an extensible templating engine. In versions on the 3.x branch prior to 3.1.5, a bug in the Jinja compiler allows an attacker that controls both the content and filename of a template to execute arbitrary Python code, regardless of if Jinja's sandbox is used. To exploit...

8. CVE-2024-49767 Werkzeug possible resource exhaustion when parsing file data in forms

   Published 2024-10-25

   Medium·CVSS 6.9 EPSS 1.1%

   Werkzeug is a Web Server Gateway Interface web application library. Applications using werkzeug.formparser.MultiPartParser corresponding to a version of Werkzeug prior to 3.0.6 to parse multipart/form-data requests (e.g. all flask applications) are vulnerable to a relatively simp...

9. CVE-2024-49766 Werkzeug safe_join not safe on Windows

   Published 2024-10-25

   Medium·CVSS 6.3 EPSS 0.78%

   Werkzeug is a Web Server Gateway Interface web application library. On Python < 3.11 on Windows, os.path.isabs() does not catch UNC paths like //server/share. Werkzeug's safe_join() relies on this check, and so can produce a path that is not safe, potentially allowing unintended...

10. CVE-2024-34069 Werkzeug's improper usage of a pathname and improper CSRF protection results in the remote command execution

    Published 2024-05-06

    High·CVSS 7.5 EPSS 3.4% Framework module

    Werkzeug is a comprehensive WSGI web application library. The debugger in affected versions of Werkzeug can allow an attacker to execute code on a developer's machine under some circumstances. This requires the attacker to get the developer to interact with a domain and subdomain...

11. CVE-2024-34064 Jinja vulnerable to HTML attribute injection when passing user input as keys to xmlattr filter

    Published 2024-05-06

    Medium·CVSS 5.4 EPSS 0.98%

    Jinja is an extensible templating engine. The xmlattr filter in affected versions of Jinja accepts keys containing non-attribute characters. XML/HTML attributes cannot contain spaces, /, >, or =, as each would then be interpreted as starting a separate attribute. If an applicatio...

12. CVE-2024-22195 Jinja vulnerable to Cross-Site Scripting (XSS)

    Published 2024-01-11

    Medium·CVSS 6.1 EPSS 0.89%

    Jinja is an extensible templating engine. Special placeholders in the template allow writing code similar to Python syntax. It is possible to inject arbitrary HTML attributes into the rendered HTML template, potentially leading to Cross-Site Scripting (XSS). The Jinja xmlattr fil...

13. CVE-2023-46136 Werkzeug vulnerable to high resource usage when parsing multipart/form-data containing a large part with CR/LF character at the beginning

    Published 2023-10-24

    High·CVSS 7.5 EPSS 1.3%

    Werkzeug is a comprehensive WSGI web application library. In versions on the 3.x branch prior to 3.0.1 and on the 2.x branch prior to 2.3.8, if an upload of a file that starts with CR or LF and then is followed by megabytes of data without these characters: all of these bytes are...

14. CVE-2023-30861 Flask vulnerable to possible disclosure of permanent session cookie due to missing Vary: Cookie header

    Published 2023-05-02

    High·CVSS 7.5 EPSS 1.3%

    Flask is a lightweight WSGI web application framework. When all of the following conditions are met, a response containing data intended for one client may be cached and subsequently sent by the proxy to other clients. If the proxy also caches Set-Cookie headers, it may send one...

15. CVE-2023-25577 Werkzeug may allow high resource usage when parsing multipart form data with many fields

    Published 2023-02-14

    High·CVSS 7.5 EPSS 1.4%

    Werkzeug is a comprehensive WSGI web application library. Prior to version 2.2.3, Werkzeug's multipart form data parser will parse an unlimited number of parts, including file parts. Parts can be a small amount of bytes, but each requires CPU time to parse and may use more memory...

16. CVE-2023-23934 Wrkzeug's incorrect parsing of nameless cookies leads to __Host- cookies bypass

    Published 2023-02-14

    Low·CVSS 3.5 EPSS 0.51%

    Werkzeug is a comprehensive WSGI web application library. Browsers may allow "nameless" cookies that look like =value instead of key=value. A vulnerable browser may allow a compromised application on an adjacent subdomain to exploit this to set a cookie like =__Host-test=bad for...

17. CVE-2020-28493 Regular Expression Denial of Service (ReDoS)

    Published 2021-02-01

    Medium·CVSS 5.3 EPSS 3.6%

    This affects the package jinja2 from 0.0.0 and before 2.11.3. The ReDoS vulnerability is mainly due to the _punctuation_re regex operator and its use of multiple wildcards. The last wildcard is the most exploitable as it searches for trailing punctuation. This issue can be mitiga...

18. CVE-2020-28724 Open Redirect in werkzeug

    Published 2020-11-18

    Medium·CVSS 6.1 EPSS 1.7%

    Open redirect vulnerability in werkzeug before 0.11.6 via a double slash in the URL.

19. CVE-2019-14806 Pallets Werkzeug Insufficient Entropy

    Published 2019-08-09

    High·CVSS 7.5 EPSS 1.9%

    Pallets Werkzeug before 0.15.3, when used with Docker, has insufficient debugger PIN randomness because Docker containers share the same machine id.

20. CVE-2019-14322 Pallets Werkzeug vulnerable to Path Traversal

    Published 2019-07-28

    High·CVSS 7.5 EPSS 55.8% Public exploit

    In Pallets Werkzeug before 0.15.5, SharedDataMiddleware mishandles drive names (such as C:) in Windows pathnames.

21. CVE-2019-1010083 Pallets Project Flask is vulnerable to Denial of Service via Unexpected memory usage

    Published 2019-07-17

    High·CVSS 7.5 EPSS 1.8%

    The Pallets Project Flask before 1.0 is affected by: unexpected memory usage. The impact is: denial of service. The attack vector is: crafted encoded JSON data. The fixed version is: 1. NOTE: this may overlap CVE-2018-1000656.

22. CVE-2016-10745 Jinja2 sandbox escape vulnerability

    Published 2019-04-08

    High·CVSS 8.6 EPSS 3.5%

    In Pallets Jinja before 2.8.1, str.format allows a sandbox escape.

23. CVE-2019-10906 Jinja2 sandbox escape via string formatting

    Published 2019-04-06

    High·CVSS 8.6 EPSS 3.6%

    In Pallets Jinja before 2.10.1, str.format_map allows a sandbox escape.

24. CVE-2018-1000656 Flask is vulnerable to Denial of Service via incorrect encoding of JSON data

    Published 2018-08-20

    High·CVSS 7.5 EPSS 3.9%

    The Pallets Project flask version Before 0.12.3 contains a CWE-20: Improper Input Validation vulnerability in flask that can result in Large amount of memory usage possibly leading to denial of service. This attack appear to be exploitable via Attacker provides JSON data in incor...

25. CVE-2016-10516 Pallets Werkzeug cross-site scripting vulnerability

    Published 2017-10-23

    Medium·CVSS 6.1 EPSS 2.0%

    Cross-site scripting (XSS) vulnerability in the render_full function in debug/tbtools.py in the debugger in Pallets Werkzeug before 0.11.11 (as used in Pallets Flask and other products) allows remote attackers to inject arbitrary web script or HTML via a field that contains an ex...

Sources: CVE.org, NVD, CISA KEV, FIRST EPSS, OSV and public exploit-reference metadata. Product matching comes from the published CVE records. A proof-of-concept means public code exists; it is not evidence of exploitation.