CVE-2026-58082: The ISO-2022 encoding module used a stack buffer sized to MB_LEN_MAX (6 bytes) for intermediate character outp

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CRITICAL 9.8REMOTEMITIGATE

CVE-2026-58082 is a critical-severity flaw (CVSS 9.8) affecting freebsd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The ISO-2022 encoding module used a stack buffer sized to MB_LEN_MAX (6 bytes) for intermediate character output. Some ISO-2022 variants can require up to 10 bytes per character, in which case conversions can trigger a stack buffer overflow of up to four bytes. An application that uses iconv(3) to convert untrusted input to or from one of the affected encodings may be vulnerable to buffer overflows if it uses one of the affected encoding module

Why this priority

Critical severity
Remotely exploitable, no login, no user action

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

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 56%)
CISA exploited list	No
Weakness	CWE-121
Published	2026-08-19
Last modified	2026-08-31

Publisher (CNA): FreeBSD · Vendor: freebsd

Last updated 2026-08-31 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-19 08:17 UTCPublished CVE record published
2026-08-31 19:02 UTCUpdated Record last modified

freebsd freebsd MITIGATE

Affected: 14.3 · 14.3 p1 · 14.3 p10 · 14.3 p11 · 14.3 p12 · 14.3 p13 · 14.3 p14 · 14.3 p15

Fixed in: no fixed release known

Safe to downgrade to: a release before 14.3

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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-2026-58082?

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

Is CVE-2026-58082 being exploited?

CVE-2026-58082 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-2026-58082 affect?

CVE-2026-58082 affects freebsd. Severity is critical (CVSS 9.8). The ISO-2022 encoding module used a stack buffer sized to MB_LEN_MAX (6 bytes) for intermediate character output. Some ISO-2022 variants can require up to 10 bytes per character, in which case conversions can trigger a stack buffer overflo

How urgent is CVE-2026-58082?

Priority 50/100. Critical severity; Remotely exploitable, no login, no user action

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References

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