Security readout for executives and security teams
Plain-English summary
A crafted DNS response can make glibc reverse-DNS lookup functions accept data from the wrong DNS section. The public record rates this high because affected applications may suffer availability impact. Exposure depends on using glibc versions described as 2.34 to 2.43 with DNS enabled through nsswitch.conf.
Executive priority
Treat this as a high-priority availability risk for Linux and embedded environments, especially operational systems relying on reverse DNS. Do not assume every glibc host is exploitable; prioritize confirmation against vendor advisories and package inventories.
Technical view
gethostbyaddr and gethostbyaddr_r in GNU C Library may mishandle responses from the configured DNS server when the DNS NSS backend is selected. The flaw is associated with CWE-125 and CVSS 7.5, with network reachability, low complexity, no authentication, and high availability impact.
Likely exposure
Likely exposure is Linux or embedded software using glibc reverse lookups through nsswitch.conf DNS. The source bundle says 2.34 to 2.43, while structured affected-version data appears incomplete, so confirm versions through vendor advisories.
Exploitation context
The CVE is not listed as KEV, and the provided sources do not state active exploitation. The described condition requires a crafted response from the configured DNS server; the bundle does not establish broader exploitability or public weaponization.
Researcher notes
Evidence is limited to the CVE description, Sourceware bug reference, and Siemens advisory link. The bundle does not provide patch details, affected downstream products, proof of exploitation, or full version matrix, so avoid over-claiming impact beyond glibc DNS reverse lookup handling.
Mitigation direction
- Identify systems running affected glibc versions and DNS NSS lookup paths.
- Check Sourceware, OS distribution, and Siemens ProductCERT guidance for fixed packages.
- Apply vendor-provided glibc or firmware updates when available.
- Review DNS resolver trust boundaries for systems performing reverse lookups.
- Prioritize internet-facing or availability-critical services using reverse DNS lookups.
Validation and detection
- Inventory glibc versions across Linux and embedded assets.
- Review nsswitch.conf for hosts entries that use DNS.
- Identify applications calling gethostbyaddr or gethostbyaddr_r directly or indirectly.
- Check vendor advisories for product-specific exposure and fixed releases.
- Track whether scanners map this CVE to installed OS packages.
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-125: 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-2026-4437 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
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:N/I:N/A:H3.93.6CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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://sourceware.org/bugzilla/show_bug.cgi?id=34014CVE reference, glibc
- https://cert-portal.siemens.com/productcert/html/ssa-082556.htmlCVE reference, siemens-SADP
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.
Out-of-bounds Read
Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.