CVE-2026-50290
@asymmetric-effort/specifyjs: CSS expression sanitization is bypassable in renderToString
Description
SpecifyJS is a declarative TypeScript user interface framework. Prior to version 0.2.136, CSS value sanitization stripped `expression(` and `url(javascript:` using simple regex, but could be bypassed with CSS unicode escapes (`\65xpression(`), null bytes, or CSS comments (`exp/**/ression(`). These CSS injection vectors only work in legacy browsers (IE6-IE10). SpecifyJS targets modern browsers. Starting in version 0.2.136, CSS sanitization now normalizes unicode escapes and strips CSS comments before pattern matching. Also checks for `behavior:`, `-moz-binding`, and `-o-link` patterns.
INFO
Published Date :
Aug. 21, 2026, 8:16 p.m.
Last Modified :
Aug. 21, 2026, 9:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-50290
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update SpecifyJS to version 0.2.136 or later.
- Validate CSS sanitization rules.
- Test for bypasses in modern browsers.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-50290.
| URL | Resource |
|---|---|
| https://github.com/asymmetric-effort/specifyjs/commit/25d1fb491d99479efdf501f5f75e0bb80c908f0a | |
| https://github.com/asymmetric-effort/specifyjs/security/advisories/GHSA-93q6-wwjh-jc6h |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-50290 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-50290
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-50290 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-50290 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Aug. 21, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-50290', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-08-21T20:07:03.359376Z'} -
New CVE Received by [email protected]
Aug. 21, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'asymmetric-effort', 'product': 'specifyjs', 'versions': [{'status': 'affected', 'version': '< 0.2.136'}]}] Added Description SpecifyJS is a declarative TypeScript user interface framework. Prior to version 0.2.136, CSS value sanitization stripped `expression(` and `url(javascript:` using simple regex, but could be bypassed with CSS unicode escapes (`\65xpression(`), null bytes, or CSS comments (`exp/**/ression(`). These CSS injection vectors only work in legacy browsers (IE6-IE10). SpecifyJS targets modern browsers. Starting in version 0.2.136, CSS sanitization now normalizes unicode escapes and strips CSS comments before pattern matching. Also checks for `behavior:`, `-moz-binding`, and `-o-link` patterns. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/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 Added CWE CWE-79 Added Reference https://github.com/asymmetric-effort/specifyjs/commit/25d1fb491d99479efdf501f5f75e0bb80c908f0a Added Reference https://github.com/asymmetric-effort/specifyjs/security/advisories/GHSA-93q6-wwjh-jc6h