CVE-2026-9358: postcss-selector-parser AST Serialization container.js toString recursion
Vulnerability summary
CVE-2026-9358 is a medium (CVSS 5.3) Improper Resource Shutdown or Release vulnerability in jupyter-base-notebook. EPSS estimates a 0.33% chance of exploitation in the next 30 days, higher than 25.6% of scored vulnerabilities. 1 public exploit is recorded.
Not severe (CVSS 5.3, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 1 · Related 1Timeline
- 24-05-2026PublishedVulnerability first disclosed.
- 15-06-2026Last modifiedVulnerability information updated.
Description
A vulnerability was determined in postcss-selector-parser up to 6.1.2/7.1.2. Affected is the function toString of the file src/selectors/container.js of the component AST Serialization. Executing a manipulation can lead to uncontrolled recursion. It is possible to launch the attack remotely. The exploit has been publicly disclosed and may be utilized. Upgrading to version 6.1.3 and 7.1.3 is able to address this issue. This patch is called 5bc698cef66f8abd12610dc623e5d67cbc0f869d. It is suggested to upgrade the affected component. The vendor explains, that according to his definition "DoS on server-side on user-generated CSS is low risk for us (since most users compile own CSS with PostCSS)." The commits were backported to 6.x branch, which was the most downloaded version.
CVSS metrics
14 scores · 7 sources · 4 versions- OSV · UbuntuEcosystem advisory · calculated5.3MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
- OSV · DebianEcosystem advisory · calculated5.3MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/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
- OSV · WolfiEcosystem advisory · calculated5.3MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
- OSV · NpmEcosystem advisory · calculated5.3MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
- OSV · ChainguardEcosystem advisory · calculated5.3MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
- NVDNIST2.1LowCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/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:XDiffers
- OSV · UbuntuEcosystem advisory · calculated4.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
- OSV · NpmEcosystem advisory · calculated4.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
- NVDNIST4.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
- NVDNIST5.0MediumAV:N/AC:L/Au:N/C:N/I:N/A:P
EPSS trend
Probability
0.33%
Chance of exploitation in the next 30 days
Percentile
26%
Versus all other CVEs
30-day change
Decrease -0.25 pp
From 0.58% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
1 found581E3A38134601C04E19B4Dfc9B459B9
Maturity: poc
Weaknesses
CWE · root cause- CWE-404Improper Resource Shutdown or ReleaseThe product does not release or incorrectly releases a resource before it is made available for re-use.
- CWE-674Uncontrolled RecursionThe product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.
Affected systems
Known conditions: network-reachable, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.
Chainguard35 products
- airflow-2All versions (No fix recorded)
- airflow-core-2All versions (No fix recorded)
- commercial-gitlab-rails-ee-19.1< 19.1.7-r3
- commercial-gitlab-rails-ee-19.2< 19.2.7-r1
- commercial-gitlab-rails-ee-19.3< 19.3.3-r1
Wolfi4 products
- jupyter-base-notebook< 7.6.3-r2
- vitess-23< 23.0.6-r3
- vitess-24< 24.0.3-r5
- vitess-24-compat< 24.0.3-r7
Debian1 product
- node-css-loaderAll versions (No fix recorded) | < 6.8.1+~cs14.1.4-1
Npm1 product
- postcss-selector-parser≥ 6.1.0, < 6.1.3 | ≥ 7.1.0, < 7.1.3
Ubuntu1 product
- node-css-loaderAll versions (No fix recorded)
5 vendors · 42 products
