CVE-2025-3266: A vulnerability, which was classified as critical, has been found in qinguoyi TinyWebServer up to 1.0

This week

HIGH 7.3REMOTEDOWNGRADE

CVE-2025-3266 is a high-severity flaw (CVSS 7.3) affecting tinywebserver. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A vulnerability, which was classified as critical, has been found in qinguoyi TinyWebServer up to 1.0. Affected by this issue is some unknown functionality of the file /http/http_conn.cpp. The manipulation of the argument name/password leads to stack-based buffer overflow. The attack may be launched remotely. The exploit has been disclosed to the public and may be used.

Why this priority

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

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

Risk facts

CVSS score	7.3 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.8% (top 43%)
CISA exploited list	No
Weakness	CWE-119, CWE-121, CWE-787
Published	2025-04-04
Last modified	2026-06-17

Publisher (CNA): VulDB · Vendor: qinguoyi

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

Am I affected?

Timeline

2025-04-04 20:15 UTCPublished CVE record published
2026-06-17 09:19 UTCUpdated Record last modified

qinguoyi tinywebserver DOWNGRADE

Affected: 1.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.0 (Debian / Ubuntu)

apt-cache madison tinywebserver sudo apt install tinywebserver=<VERSION_BEFORE_1.0> sudo apt-mark hold tinywebserver

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

dnf --showduplicates list tinywebserver sudo dnf downgrade tinywebserver-<VERSION_BEFORE_1.0> sudo dnf versionlock add tinywebserver

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-2025-3266?

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

Is CVE-2025-3266 being exploited?

CVE-2025-3266 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-2025-3266 affect?

CVE-2025-3266 affects tinywebserver. Severity is high (CVSS 7.3). A vulnerability, which was classified as critical, has been found in qinguoyi TinyWebServer up to 1.0. Affected by this issue is some unknown functionality of the file /http/http_conn.cpp. The manipulation of the argument name/password lead

How urgent is CVE-2025-3266?

Priority 50/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2025-3268 MEDIUM 5.3 UPGRADE A vulnerability has been found in qinguoyi TinyWebServer up to 1.0 and classified as critical
CVE-2025-3267 MEDIUM 6.3 DOWNGRADE A vulnerability, which was classified as critical, was found in qinguoyi TinyWebServer up to 1.0

References

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