Security readout for executives and security teams
Plain-English summary
CVE-2026-28808 lets some Erlang OTP inets web servers expose CGI scripts that administrators expected to be protected. The risk is unauthorized network access to sensitive CGI endpoints when ScriptAlias maps scripts outside DocumentRoot and directory authorization rules are relied on.
Executive priority
Treat as high priority where inets httpd exposes CGI over a network. Business urgency depends on whether protected CGI scripts exist; prioritize internet-facing or partner-facing services first.
Technical view
In inets httpd, mod_auth checks directory rules against a DocumentRoot-relative path while mod_cgi executes the ScriptAlias-resolved path. That mismatch can bypass directory-based authorization for CGI scripts served through script_alias. Sources associate the bug with mod_alias.erl, mod_auth.erl, and mod_cgi.erl.
Likely exposure
Exposure is likely limited to Erlang OTP deployments using the inets httpd server with CGI enabled, script_alias configured, and directory-based access controls protecting those CGI scripts. Generic Erlang applications are not automatically exposed by OTP presence alone.
Exploitation context
The source bundle marks KEV as false and provides no evidence of active exploitation. The CVSS 4.0 score is 8.3 with network attack vector, low complexity, no privileges, and no user interaction, but an attacker must reach a vulnerable CGI path and configuration.
Researcher notes
The key condition is a path interpretation mismatch between authorization and CGI execution. Validate configuration state before assuming impact. The source bundle names affected version ranges and patch commits, but does not provide exploit telemetry or broad product impact beyond Erlang OTP inets.
Mitigation direction
- Upgrade affected OTP/inets deployments to vendor-fixed releases identified in Erlang guidance.
- Prioritize OTP 28.4.2, 27.3.4.10, 26.2.5.19 or later where applicable.
- Review ScriptAlias CGI paths that rely on directory authorization rules.
- If upgrade timing is unclear, check the Erlang advisory before applying compensating controls.
- Restrict network access to sensitive CGI endpoints until remediation is complete.
Validation and detection
- Inventory OTP and inets versions on systems running inets httpd.
- Identify httpd configurations with CGI and script_alias enabled.
- Confirm protected CGI directories are not served from outside DocumentRoot unexpectedly.
- Verify directory authentication still applies after upgrade or configuration change.
- Review access logs for unexpected unauthenticated CGI requests.
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-551: 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 lookupCWE-863: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. 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-2026-28808 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
- 8.3 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
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
2 official scoresWe 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:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N——EEFCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N2.25.2redhat-SADPVulnerability scoring details
Base CVSS 4.0 score
8.3HighVector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
Base CVSS 3.1 score
7.4HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
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.
- ADP timelineredhat-SADP
Made public.
- CVE publishedCVE Program
The CVE record was published.
- ADP timelineredhat-SADP
Reported to Red Hat.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2026-04-07T13:01:42.326Z: Reported to Red Hat.
- 2026-04-07T12:28:16.056Z: Made public.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/erlang/otp/security/advisories/GHSA-3vhp-h532-mc3fCVE reference, EEF · vendor-advisory, related
- https://cna.erlef.org/cves/CVE-2026-28808.htmlCVE reference, EEF · related
- https://osv.dev/vulnerability/EEF-CVE-2026-28808CVE reference, EEF · related
- https://www.erlang.org/doc/system/versions.html#order-of-versionsCVE reference, EEF · x_version-scheme
- https://github.com/erlang/otp/commit/8fc71ac6af4fbcc54103bec2983ef22e82942688CVE reference, EEF · patch
- https://github.com/erlang/otp/commit/9dfa0c51eac97866078e808dec2183cb7871ff7cCVE reference, EEF · patch
- https://access.redhat.com/security/cve/CVE-2026-28808CVE reference, redhat-SADP · vdb-entry, x_refsource_REDHAT
- RHBZ#2455909CVE reference, redhat-SADP · issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-28808.jsonCVE reference, redhat-SADP · x_sadp-csaf-vex
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.
Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
Incorrect Behavior Order: Authorization Before Parsing and Canonicalization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Incorrect Authorization
Incorrect Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.