CVE-2021-32723
Regular Expression Denial of Service (ReDoS) in Prism
Prism is a syntax highlighting library. Some languages before 1.24.0 are vulnerable to Regular Expression Denial of Service (ReDoS). When Prism is used to highlight untrusted (user-given) text, an attacker can craft a string that will take a very very long time to highlight. This problem has been fixed in Prism v1.24. As a workaround, do not use ASCIIDoc or ERB to highlight untrusted text. Other languages are not affected and can be used to highlight untrusted text.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Regular Expression Denial of Service (ReDoS) in Prism
Prism is a syntax highlighting library. Some languages before 1.24.0 are vulnerable to Regular Expression Denial of Service (ReDoS). When Prism is used to highlight untrusted (user-given) text, an attacker can craft a string that will take a very very long time to highlight. This problem has been fixed in Prism v1.24. As a workaround, do not use ASCIIDoc or ERB to highlight untrusted text. Other languages are not affected and can be used to highlight untrusted text.
- Record
CVE-2021-32723- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
EUVDEUVD-2021-1326
Prism is a syntax highlighting library. Some languages before 1.24.0 are vulnerable to Regular Expression Denial of Service (ReDoS). When Prism is used to highlight untrusted (user-given) text, an attacker can craft a string that will take a very very long time to highlight. This problem has been fixed in Prism v1.24. As a workaround, do not use ASCIIDoc or ERB to highlight untrusted text. Other languages are not affected and can be used to highlight untrusted text.
- Record
EUVD-2021-1326- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-gj77-59wh-66hg
Regular Expression Denial of Service (ReDoS) in Prism
Some languages before 1.24.0 are vulnerable to Regular Expression Denial of Service (ReDoS).
Impact
When Prism is used to highlight untrusted (user-given) text, an attacker can craft a string that will take a very very long time to highlight. Do not use the following languages to highlight untrusted text.
- ASCIIDoc
- ERB
Other languages are not affected and can be used to highlight untrusted text.
Patches
This problem has been fixed in Prism v1.24.
References
- PrismJS/prism#2774
- PrismJS/prism#2688
- Record
GHSA-gj77-59wh-66hg- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
NVD
Prism is a syntax highlighting library. Some languages before 1.24.0 are vulnerable to Regular Expression Denial of Service (ReDoS). When Prism is used to highlight untrusted (user-given) text, an attacker can craft a string that will take a very very long time to highlight. This problem has been fixed in Prism v1.24. As a workaround, do not use ASCIIDoc or ERB to highlight untrusted text. Other languages are not affected and can be used to highlight untrusted text.
- Record
CVE-2021-32723- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:H - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:N/A:P - Weakness
- CWE-400
- Updated
- 2026-11-02
OSV
Prism is a syntax highlighting library. Some languages before 1.24.0 are vulnerable to Regular Expression Denial of Service (ReDoS). When Prism is used to highlight untrusted (user-given) text, an attacker can craft a string that will take a very very long time to highlight. This problem has been fixed in Prism v1.24. As a workaround, do not use ASCIIDoc or ERB to highlight untrusted text. Other languages are not affected and can be used to highlight untrusted text.
- Record
CVE-2021-32723- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVGHSA-gj77-59wh-66hg
Regular Expression Denial of Service (ReDoS) in Prism
Some languages before 1.24.0 are vulnerable to Regular Expression Denial of Service (ReDoS).
Impact
When Prism is used to highlight untrusted (user-given) text, an attacker can craft a string that will take a very very long time to highlight. Do not use the following languages to highlight untrusted text.
- ASCIIDoc
- ERB
Other languages are not affected and can be used to highlight untrusted text.
Patches
This problem has been fixed in Prism v1.24.
References
- PrismJS/prism#2774
- PrismJS/prism#2688
- Record
GHSA-gj77-59wh-66hg- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2021-32723
Prism is a syntax highlighting library. Some languages before 1.24.0 are vulnerable to Regular Expression Denial of Service (ReDoS). When Prism is used to highlight untrusted (user-given) text, an attacker can craft a string that will take a very very long time to highlight. This problem has been fixed in Prism v1.24. As a workaround, do not use ASCIIDoc or ERB to highlight untrusted text. Other languages are not affected and can be used to highlight untrusted text.
- Record
UBUNTU-CVE-2021-32723- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:H - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVCLSA-2026-1793304056 No score
TuxCare security update for prismjs (6 CVEs)
TuxCare rebuilt prismjs to address 6 CVEs. Fixed in 1.17.1-tuxcare.1.
- Record
CLSA-2026-1793304056- Updated
- 2026-11-02
OSVROOT-APP-NPM-CVE-2021-32723 No score
CVE-2021-32723 in prismjs - Patched by Root
Root has patched CVE-2021-32723 in the prismjs package for Root:npm. Multiple fixed versions available.
- Record
ROOT-APP-NPM-CVE-2021-32723- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
prismjsnpm |
before 1.24.0 | 1.24.0 |
prismjsTuxCare:npm From an advisory covering 6 CVEs |
1.17.1-tuxcare.0 up to 1.17.1-tuxcare.1, plus listed versions 1.17.1 |
1.17.1-tuxcare.1 |
prismjsRoot:npm |
before 1.17.1-aikido.1 | 1.17.1-aikido.1 |
@rootio/prismjsRoot:npm |
before 1.17.1-root.io.1 | 1.17.1-root.io.1 |
node-prismjsUbuntu:20.04:LTS |
All versions, plus listed versions 1.11.0+dfsg-21.11.0+dfsg-3 |
None known |
node-prismjsUbuntu:22.04:LTS |
All versions, plus listed versions 1.23.0+dfsg-11.25.0+dfsg-11.27.0+dfsg+~1.26.0-1 |
None known |
node-prismjsUbuntu:24.04:LTS |
All versions, plus listed versions 1.29.0+dfsg+~1.26.0-1 |
None known |
node-prismjsUbuntu:25.10 |
All versions, plus listed versions 1.29.0+dfsg+~1.26.0-11.30.0+dfsg+~1.26.5-1 |
None known |
node-prismjsUbuntu:26.10 |
All versions, plus listed versions 1.30.0+dfsg+~1.26.6-1 |
None known |
node-prismjsUbuntu:26.04:LTS |
All versions, plus listed versions 1.30.0+dfsg+~1.26.5-11.30.0+dfsg+~1.26.5-21.30.0+dfsg+~1.26.6-1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-32723 is a high vulnerability (CVSS 7.4) in Prismjs Prism, published June 28, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.42%, the 73rd percentile. Fixed in prismjs 1.24.0.