CVE-2026-58082

Memory corruption via undersized ISO-2022 stack buffer

Published Aug 19, 2026 · Updated Aug 19, 2026

Stack buffer overflow in iconv(3) in FreeBSD allows attackers to corrupt memory via crafted ISO-2022 text in affected releases. The _ISO2022_sputwchar() conversion path uses an intermediate stack buffer sized to MB_LEN_MAX even though some ISO-2022 variants can emit up to 10 bytes, so conversion can write up to four bytes past that stack buffer. Exposure depends on an application converting untrusted text on FreeBSD 14.3 before 14.3-RELEASE-p16, 14.4 before 14.4-RELEASE-p7, 15.0 before 15.0-RELEASE-p11, or 15.1 before 15.1-RELEASE-p1; the published impact is memory corruption and possible process crashes, with no vendor claim of code execution.

CVSS severity9.8
Critical
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack buffer overflow in iconv(3) in FreeBSD allows attackers to corrupt memory via crafted ISO-2022 text in affected releases. The _ISO2022_sputwchar() conversion path uses an intermediate stack buffer sized to MB_LEN_MAX even though some ISO-2022 variants can emit up to 10 bytes, so conversion can write up to four bytes past that stack buffer. Exposure depends on an application converting untrusted text on FreeBSD 14.3 before 14.3-RELEASE-p16, 14.4 before 14.4-RELEASE-p7, 15.0 before 15.0-RELEASE-p11, or 15.1 before 15.1-RELEASE-p1; the published impact is memory corruption and possible process crashes, with no vendor claim of code execution.

The record

CVE
CVE-2026-58082
Published
Aug 19, 2026
Updated
Aug 19, 2026
Vendor
The FreeBSD Project
Product
FreeBSD
Classifications
Unavailable
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Aug 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=14.3-RELEASE <p16
  2. Affected versionversion=14.4-RELEASE <p7
  3. Affected versionversion=15.0-RELEASE <p11
  4. Affected versionversion=15.1-RELEASE <p1

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

The FreeBSD Project · FreeBSDversion=14.3-RELEASE <p16; version=14.4-RELEASE <p7; version=15.0-RELEASE <p11; version=15.1-RELEASE <p1

Published CVSS scores

9.8TenableCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5TenableAV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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