Security readout for executives and security teams
Plain-English summary
FreeBSD’s iconv character-conversion library can write beyond allocated memory when certain encodings process untrusted data. A vulnerable application could crash or potentially allow code execution, data access, or tampering. Risk depends on whether applications actually invoke the affected HZ, UTF-7, VIQR, or ZW conversion modules.
Executive priority
Treat as an urgent investigation and patching priority for internet-facing or data-processing FreeBSD services. The theoretical impact is critical, but practical exposure is conditional on application behavior. Establish affected conversion paths quickly, follow FreeBSD’s advisory, and avoid claiming an active incident without separate evidence.
Technical view
Affected iconv(3) modules insufficiently validate caller-supplied output-buffer capacity before writing converted characters, causing a heap-based buffer overflow. The cited releases are FreeBSD 14.3, 14.4, 15.0, and 15.1. Exploitability requires an application converting attacker-controlled input to or from an affected encoding.
Likely exposure
Prioritize exposed services on the cited FreeBSD releases that convert externally supplied text, documents, messages, or protocol data through iconv(3). Systems without affected releases, untrusted conversion paths, or the named encoding modules have lower likely exposure, but the bundle does not establish complete product boundaries.
Exploitation context
The CVSS 3.1 score is 9.8, reflecting network reachability, low complexity, no required privileges, and potentially severe impact. However, KEV is false, and the provided sources do not establish active exploitation, public exploit availability, or observed attacks.
Researcher notes
CWE-122 applies. The bundle identifies improper output-bound checks across several encoding modules but provides no crash signatures, fixed versions, patch identifiers, exploit samples, or confirmed exploitation. Researchers should use the vendor advisory and CVE record to validate remediation boundaries without assuming every iconv consumer is reachable or exploitable.
Mitigation direction
- Review the FreeBSD advisory and apply its prescribed security update or patch.
- Inventory applications using iconv(3) on the cited FreeBSD releases.
- Temporarily prevent untrusted conversions involving HZ, UTF-7, VIQR, or ZW where operationally feasible.
- Monitor vendor guidance for clarified affected versions and remediation details.
Validation and detection
- Confirm each system’s FreeBSD release against the four cited affected releases.
- Identify applications and libraries that call iconv(3) with untrusted input.
- Check whether conversion paths permit HZ, UTF-7, VIQR, or ZW.
- Verify remediation against the fixed release or patch level specified by FreeBSD.
- Retest affected conversion workflows after remediation without using malicious payloads.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-122: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-58081 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://security.freebsd.org/advisories/FreeBSD-SA-26:49.iconv.ascCVE reference, freebsd · vendor-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Heap-based Buffer Overflow
Heap-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.