CVE-2026-48856

Description

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 17.0 before 29.0.2, 28.5.0.2 and 27.3.4.13 corresponding to inets from 5.10 before 9.7.1, 9.6.2.2 and 9.3.2.6.

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CVSS v3.1 Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS — Exploit Prediction

0.0034

Probability of exploitation

0.26%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-601 CWE-601

Affected Products

Vendor	Product	Versions
erlang	erlang\/inets	5.10 — 9.3.2.6
erlang	erlang\/inets	9.6 — 9.6.2.2
erlang	erlang\/inets	9.7 — 9.7.1
erlang	erlang\/otp	17.0 — 27.3.4.13
erlang	erlang\/otp	28.0 — 28.5.0.2
erlang	erlang\/otp	29.0 — 29.0.2

References

Advisories & Patches

https://github.com/erlang/otp/commit/688d748d6f7a6a06b13b662a1d3de8af97079612 https://github.com/erlang/otp/security/advisories/GHSA-m75x-4vwg-ggjh

Other References

https://cna.erlef.org/cves/CVE-2026-48856.html https://osv.dev/vulnerability/EEF-CVE-2026-48856 https://www.erlang.org/doc/system/versions.html#order-of-versions

Frequently Asked Questions

What is CVE-2026-48856? +

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 17.0 before 29.0.2, 28.5.0.2 and 27.3.4.13 corresponding to inets from 5.10 before 9.7.1, 9.6.2.2 and 9.3.2.6. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-48856? +

CVE-2026-48856 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0034, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-48856? +

CVE-2026-48856 affects products from erlang, specifically: erlang\/inets, erlang\/otp. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-48856? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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