CVE-2026-48856 — httpc leaks Authorization header to cross-origin redirect targets
Sensitive Data Exposure vulnerability in Erlang OTP inets (httpc_response module) allows Retrieve Embedded Sensitive Data. The httpc client forwards the Authorization and Proxy-Authorization request headers to redirect targets without checking whether the redirect crosses an origin boundary. httpc_response:redirect/2 constructs the redirected request by updating only the host field of the header record; all other fields (including authorization and proxy_authorization) are copied verbatim. The redirect target host is never compared against the original host. autoredirect defaults to true, so this affects all httpc callers that do not explicitly disable automatic redirects. An attacker who controls a server that the victim contacts via httpc can issue a cross-origin 3xx redirect to a server they also control. The Authorization header (including Basic credentials derived from URL userinfo via httpc_request:handle_user_info/2) is forwarded to the redirect target, allowing credential theft. The same applies to the Proxy-Authorization header. This vulnerability is associated with program files lib/inets/src/http_client/httpc_response.erl. This issue affects OTP from OTP 17.0 before OTP 27.3.4.19, OTP 28.5.0.8, and OTP 29.1.2, corresponding to inets from 5.10 before 9.3.2.8, 9.6.2.4, and 9.8.1. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.3% (30-day exploitation probability)+4
- Technical severity (medium)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented mitigation — cna.erlef.org (NIST National Vulnerability Database)
- Documented mitigation — github.com (NIST National Vulnerability Database)
- Documented mitigation — osv.dev (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Erlang Erlang/inets, Erlang Erlang/otp).
- Apply the documented mitigations until a definitive fix is available.
- Search available logs for exploit probes matching the vulnerability class (open redirect), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Erlang | Erlang/inets | ≥ 5.10 and < 9.3.2.6≥ 9.6 and < 9.6.2.2≥ 9.7 and < 9.7.1 | Vulnerable | NIST National Vulnerability Database |
| Erlang | Erlang/otp | ≥ 17.0 and < 27.3.4.13≥ 28.0 and < 28.5.0.2≥ 29.0 and < 29.0.2 | Vulnerable | NIST National Vulnerability Database |
| Erlang | Erlang/otp | ≥ 17.0≥ 5.10≥ 84adefa331c4159d432d22840663c38f155cd4c1 and < f78fae9294886f95545a2212671282eda230def1 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.1 | CVSS 4.0 | High | — | — | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db via NIST National Vulnerability Database |
| 7.1 | CVSS 4.0 | High | — | — | EEF via CVE Program (cve.org) e CISA ADP |
| 6.5 | CVSS 3.1 | Medium | 2.8 | 3.6 | nvd@nist.gov via NIST National Vulnerability Database |
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.34%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products removed · 3
- Affected products added · erlang/otp
- Affected products added · erlang/otp
- SSVC assessment updated
- Record published
- Fix documented
- CVSS changed · 6.5
- Source status changed · → Modified
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× References added · Oct 15, 2026 – Oct 15, 2026
- 2× Official description updated · Oct 13, 2026 – Oct 15, 2026
References
6 on the record
- github.com/erlang/otp/security/advisories/GHSA-m75x-4vwg-ggjh
- github.com/erlang/otp/commit/688d748d6f7a6a06b13b662a1d3de8af97079612
- github.com/erlang/otp/commit/f78fae9294886f95545a2212671282eda230def1
- cna.erlef.org/cves/CVE-2026-48856.html
- osv.dev/vulnerability/EEF-CVE-2026-48856
- www.erlang.org/doc/system/versions.html
Elsewhere on this site
Related CVEs (same products)
- Medium CVE-2026-96596 erl_tar:extract/2 loops forever on a GNU sparse member with a trailing hole 1d
- High CVE-2026-94200 TLS 1.3 client ticket store crashed by NewSessionTicket with empty early_data extension in ssl 1d
- Medium CVE-2026-105236 TLS 1.2 session resumption in ssl crosses SNI virtual-host client-certificate trust boundaries 1d
- High CVE-2026-59251 Allocation of Resources Without Limits or Throttling in Erlang Erlang/otp Jul 27, 2026
- High CVE-2026-58227 Uncontrolled Recursion in Erlang Erlang/otp Jul 27, 2026
- High CVE-2026-55953 The Erlang/OTP ssl TLS 1.2 (and earlier) and DTLS client does not verify that the cipher… Jul 27, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-48856 is "httpc leaks Authorization header to cross-origin redirect targets", rated Medium. It affects Erlang/inets (Erlang); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.5 describes technical severity. EPSS 0.34% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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