CVE-2023-27728: Nginx NJS v0.7.10 was discovered to contain a segmentation violation via the function njs_dump_is_recursive at

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HIGH 7.5REMOTEWATCHLISTDOWNGRADE

CVE-2023-27728 is a high-severity flaw (CVSS 7.5) affecting njs. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Nginx NJS v0.7.10 was discovered to contain a segmentation violation via the function njs_dump_is_recursive at src/njs_vmcode.c.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action
On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.7% (top 45%)
CISA exploited list	No
Weakness	CWE-125
Published	2023-04-09
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: f5

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-04-09 20:15 UTCPublished CVE record published
2026-06-17 05:45 UTCUpdated Record last modified

f5 njs DOWNGRADE

Affected: 0.7.10

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.7.10

1. Check installed version

apt-cache policy njs || rpm -q njs || njs --version

2. No fixed release: DOWNGRADE to a release before 0.7.10 (Debian / Ubuntu)

apt-cache madison njs sudo apt install njs=<VERSION_BEFORE_0.7.10> sudo apt-mark hold njs

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list njs sudo dnf downgrade njs-<VERSION_BEFORE_0.7.10> sudo dnf versionlock add njs

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-27728?

njs: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2023-27728 being exploited?

CVE-2023-27728 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-27728 affect?

CVE-2023-27728 affects njs. Severity is high (CVSS 7.5). Nginx NJS v0.7.10 was discovered to contain a segmentation violation via the function njs_dump_is_recursive at src/njs_vmcode.c.

How urgent is CVE-2023-27728?

Priority 55/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

nginx vulnerabilities · F5 BIG-IP vulnerabilities

Related CVEs

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CVE-2023-27730 HIGH 7.5 DOWNGRADE Nginx NJS v0.7.10 was discovered to contain a segmentation violation via the function njs_lvlhsh_find at src/n
CVE-2023-27729 HIGH 7.5 DOWNGRADE Nginx NJS v0.7.10 was discovered to contain an illegal memcpy via the function njs_vmcode_return at src/njs_vm
CVE-2023-27727 HIGH 7.5 DOWNGRADE Nginx NJS v0.7.10 was discovered to contain a segmentation violation via the function njs_function_frame at sr
CVE-2022-43286 CRITICAL 9.8 DOWNGRADE Nginx NJS v0.7.2 was discovered to contain a heap-use-after-free bug caused by illegal memory copy in the func

References

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