CVE-2025-27789

Service interruption via quadratic replacement parsing

Published Mar 11, 2025 · Updated Mar 11, 2025

Algorithmic complexity in Babel before 7.26.10 and 8.0.0-alpha.17 allows attackers to cause a service hang via crafted replacements. The generated wrapRegExp helper parses named-capture substitutions with an ambiguous regular expression that backtracks quadratically across repeated unterminated $< sequences. Exposure requires transformed named capturing groups, a replace call on that RegExp, and attacker-controlled replacement text; CPU exhaustion can hang the generated application.

CVSS severity6.2
Medium
EPSS probability0.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Algorithmic complexity in Babel before 7.26.10 and 8.0.0-alpha.17 allows attackers to cause a service hang via crafted replacements. The generated wrapRegExp helper parses named-capture substitutions with an ambiguous regular expression that backtracks quadratically across repeated unterminated $< sequences. Exposure requires transformed named capturing groups, a replace call on that RegExp, and attacker-controlled replacement text; CPU exhaustion can hang the generated application.

The record

CVE
CVE-2025-27789
Published
Mar 11, 2025
Updated
Mar 11, 2025
Vendor
Babel
Product
Babel
Classifications
CWE-1333, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 11, 2025CVE publishedPublication date reported by the CVE source.
  2. Mar 11, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 7.26.10
  2. Affected versionversion=>= 8.0.0-alpha.0, < 8.0.0-alpha.17

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Babel · Babelversion=< 7.26.10; version=>= 8.0.0-alpha.0, < 8.0.0-alpha.17

Published CVSS scores

6.2GitHubCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1333Inefficient Regular Expression Complexity
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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