CVE-2026-16756: Missing connection and header-read timeouts and the absence of a concurrent-connection cap in the default serv

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HIGH 7.5REMOTE

CVE-2026-16756 is a high-severity flaw (CVSS 7.5) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Missing connection and header-read timeouts and the absence of a concurrent-connection cap in the default serve() path of Amazon aws-smithy-http-server might allow remote attackers to cause a denial of service by opening many connections and sending partial requests that are never completed, exhausting server sockets and tasks. To mitigate this issue, users should upgrade to aws-smithy-http-server 0.66.5 or later.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.8% (top 45%)
CISA exploited list	No
Weakness	CWE-770
Published	2026-07-23
Last modified	2026-10-24

Publisher (CNA): AMZN

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Timeline

2026-07-23 19:16 UTCPublished CVE record published
2026-10-24 13:10 UTCUpdated Record last modified

Exact fixes by distribution

Rust (Cargo) · aws-smithy-http-server · FIXED · 0.66.5 · vulnerable: <= 0.66.4 · source

Set aws-smithy-http-server >= 0.66.5 in Cargo.toml, then run: cargo update -p aws-smithy-http-server

Fedora 46 · gnome-shell-extension-tiling-assistant · FIXED · 56-1.fc46 · FEDORA-2026-ebf66a5321 · source

sudo dnf upgrade --advisory=FEDORA-2026-ebf66a5321

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-2026-16756?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Is CVE-2026-16756 being exploited?

CVE-2026-16756 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-2026-16756 affect?

CVE-2026-16756 affects affected software. Severity is high (CVSS 7.5). Missing connection and header-read timeouts and the absence of a concurrent-connection cap in the default serve() path of Amazon aws-smithy-http-server might allow remote attackers to cause a denial of service by opening many connections an

How urgent is CVE-2026-16756?

Priority 45/100. High severity; Remotely exploitable, no login, no user action

Software pages

AWS vulnerabilities

References

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