Public proof of conceptFix available

CVE-2021-35556

Q: Is CVE-2021-35556 actively exploited?

A proof-of-concept exploit exists for CVE-2021-35556, but active exploitation has not been confirmed at this time.

Q: What is the CVSS score for CVE-2021-35556?

CVE-2021-35556 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

A public proof of concept exists; no exploitation attested.

Published2021-10-20
Fixed in17.0.1 · 11.0.13 · 8.0.311 · 7.0.321 · 1.8.0 · 1.7.0
WeaknessCWE-693

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Vulnerability in the Java SE, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: Swing). Supported versions that are affected are Java SE: 7u311, 8u301, 11.0.12, 17; Oracle GraalVM Enterprise Edition: 20.3.3 and 21.2.0. Easily exploitable vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise Java SE, Oracle GraalVM Enterprise Edition. Successful attacks of this vulnerability can result in unauthorized ability to cause a partial denial of service (partial DOS) of Java SE, Oracle GraalVM Enterprise Edition. Note: This vulnerability applies to Java deployments, typically in clients running sandboxed Java Web Start applications or sandboxed Java applets, that load and run untrusted code (e.g., code that comes from the internet) and rely on the Java sandbox for security. This vulnerability does not apply to Java deployments, typically in servers, that load and run only trusted code (e.g., code installed by an administrator). CVSS 3.1 Base Score 5.3 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).

Timeline

dates in UTC

2021-10-2011:16CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-35556?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-35556?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

OSV

java

Branch	Affected	Fixed in	Source
17.0	≥ 12.0.0, < 17.0.1	17.0.1	OSV
11.0	≥ 9.0.0, < 11.0.13	11.0.13	OSV
8.0	≥ 8.0.0, < 8.0.311	8.0.311	OSV
7.0	≥ 7.0.0, < 7.0.321	7.0.321	OSV
1.8	≥ 1.8.0, < 1.8.0	1.8.0	OSV
1.7	< 1.7.0	1.7.0	OSV

java-min

Branch	Affected	Fixed in	Source
17.0	≥ 12.0.0, < 17.0.1	17.0.1	OSV
11.0	≥ 9.0.0, < 11.0.13	11.0.13	OSV
8.0	≥ 8.0.0, < 8.0.311	8.0.311	OSV
7.0	≥ 7.0.0, < 7.0.321	7.0.321	OSV
1.8	≥ 1.8.0, < 1.8.0	1.8.0	OSV
1.7	< 1.7.0	1.7.0	OSV

jre

Branch	Affected	Fixed in	Source
17.0	≥ 12.0.0, < 17.0.1	17.0.1	OSV
11.0	≥ 9.0.0, < 11.0.13	11.0.13	OSV
8.0	≥ 8.0.0, < 8.0.311	8.0.311	OSV
7.0	≥ 7.0.0, < 7.0.321	7.0.321	OSV
1.8	≥ 1.8.0, < 1.8.0	1.8.0	OSV
1.7	< 1.7.0	1.7.0	OSV

14 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

java-1.8.0-openjdkAlmaLinux:8all versions · fixed in 1:1.8.0.312.b07-1.el8_4and 19 other packages
java-11-openjdkAlmaLinux:8all versions · fixed in 1:11.0.13.0.8-1.el8_4and 22 other packages
java-17-openjdkAlmaLinux:8all versions · fixed in 1:17.0.1.0.12-2.el8_5and 22 other packages

Full record on NVD

Fix

Update java to 17.0.1 · 11.0.13 · 8.0.311 · 7.0.321 · 1.8.0 · 1.7.0

Advisories and patches

www.oracle.comPatch · Vendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionpoc2024-06-24
OpenCVESSVC decisionpoc—
CNACVSS 3.15.3read 2026-10-23
NVDCVSS 3.15.3read 2026-10-23
NVDCVSS 2.05read 2026-10-23
CISA-ADPweakness (CWE)CWE-6932026-05-28
FIRST EPSSEPSS score8.5 %2026-10-23
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Published: 2021-10-20
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-35556?

Is CVE-2021-35556 actively exploited?

A proof-of-concept exploit exists for CVE-2021-35556, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2021-35556?

CVE-2021-35556 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

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