CVE-2026-27784: The 32-bit implementation of NGINX Open Source has a vulnerability in the ngx_http_mp4_module module, which mi

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HIGH 7.8WATCHLISTUPGRADE

CVE-2026-27784 is a high-severity flaw (CVSS 7.8) affecting nginx open source. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The 32-bit implementation of NGINX Open Source has a vulnerability in the ngx_http_mp4_module module, which might allow an attacker to over-read or over-write NGINX worker memory resulting in its termination, using a specially crafted MP4 file. The issue only affects 32-bit NGINX Open Source if it is built with the ngx_http_mp4_module module and the mp4 directive is used in the configuration file. Additionally, the attack is possible only if an a

Why this priority

High severity
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	1.1% (top 35%)
CISA exploited list	No
Weakness	CWE-190
Published	2026-03-24
Last modified	2026-07-15

Publisher (CNA): F5 Networks · Vendor: f5

Last updated 2026-07-15 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-24 15:16 UTCPublished CVE record published
2026-07-15 02:19 UTCUpdated Record last modified

f5 nginx open source UPGRADE

Affected: >= 1.1.19 and < 1.28.3 · >= 1.29.0 and < 1.29.7

Fixed in: 1.28.3, 1.29.7

Safe to downgrade to: a release before 1.1.19

1. Check installed version

apt-cache policy nginx-open-source || rpm -q nginx-open-source || nginx-open-source --version

2. UPGRADE to 1.28.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade nginx-open-source

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade nginx-open-source

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 1.1.19 (Debian / Ubuntu)

apt-cache madison nginx-open-source sudo apt install nginx-open-source=<VERSION_BEFORE_1.1.19> sudo apt-mark hold nginx-open-source

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list nginx-open-source sudo dnf downgrade nginx-open-source-<VERSION_BEFORE_1.1.19> sudo dnf versionlock add nginx-open-source

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-2026-27784?

nginx open source: upgrade to 1.28.3, 1.29.7. Exact commands for each OS are on this page.

Is CVE-2026-27784 being exploited?

CVE-2026-27784 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-2026-27784 affect?

CVE-2026-27784 affects nginx open source. Severity is high (CVSS 7.8). The 32-bit implementation of NGINX Open Source has a vulnerability in the ngx_http_mp4_module module, which might allow an attacker to over-read or over-write NGINX worker memory resulting in its termination, using a specially crafted MP4 f

How urgent is CVE-2026-27784?

Priority 48/100. High severity; On your watchlist

Software pages

nginx vulnerabilities · F5 BIG-IP vulnerabilities

Related CVEs

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CVE-2026-42945 HIGH 8.1 UPGRADE UPGRADE NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_rewrite_module module
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CVE-2026-42934 MEDIUM 4.8 UPGRADE UPGRADE NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_charset_module module

References

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