CVE-2026-49356 | Babel: Arbitrary File Read via sourceMappingURL Comment in @babel/core

Babel is a compiler for writing next generation JavaScript. Prior to 8.0.0-rc.6 and 7.29.6, @babel/core affected by an arbitrary file read via a sourceMappingURL comment. Using @babel/core to compile maliciously crafted code can allow an attacker to read any source map from the system that is running Babel, if the attacker controls the input source code, can read the output source code, and knows the path of the source map file that they want to read. This vulnerability is fixed in 8.0.0-rc.6 and 7.29.6.

Published: 2026-06-22 Last update: 2026-06-26 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-49356 is rated Low Risk (13.5/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.11%). Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-49356

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-23 0.01% 0.11% +0.10%
2 2026-06-13 — 0.01% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-49356

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.2 3.1 LOW
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 1.4 1.4 [email protected]
3.6 3.1 LOW
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 1.8 1.4 [email protected]

Weakness enumeration for CVE-2026-49356

GitHub Security Advisory for CVE-2026-49356

GHSA-4x5r-pxfx-6jf8 · Severity: low · Ecosystem: npm — @babel/core: Arbitrary File Read via sourceMappingURL Comment

OS Trackers for CVE-2026-49356

vendor priority summary link
debian not yet assigned CVE-2026-49356 not yet assigned priority: Debian including 1 source packages (node-babel7), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 5. https://security-tracker.debian.org/tracker/CVE-2026-49356
ubuntu medium CVE-2026-49356 medium priority: Ubuntu including 1 source packages (babel), 5 status rows across 5 suites (jammy, noble, questing, resolute, upstream): DNE 4, needs-triage 1. https://ubuntu.com/security/CVE-2026-49356

Affected software / configurations for CVE-2026-49356

Vendor Product Version Raw CPE
babel babel < 7.29.6 cpe:2.3:a:babel:babel:*:*:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:alpha0:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:alpha1:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:alpha10:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:alpha11:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:alpha12:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:alpha13:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:alpha14:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:alpha15:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:alpha16:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:alpha17:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:alpha2:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:alpha3:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:alpha4:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:alpha5:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:alpha6:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:alpha7:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:alpha8:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:alpha9:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:beta0:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:beta1:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:beta2:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:beta3:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:beta4:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:rc1:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:rc2:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:rc3:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:rc4:*:*:*:*:*:*
babel babel 8.0.0 cpe:2.3:a:babel:babel:8.0.0:rc5:*:*:*:*:*:*

References for CVE-2026-49356

cvelogic Threat Intelligence