Medium severity · published Sep 1, 2026
CVE-2026-71562
httpc does not bound server-supplied numeric header values before integer conversion
6.3
CVSS
0.6%
EPSS
No
On KEV
Description
Improper Validation of Specified Quantity in Input vulnerability in Erlang/OTP inets httpc allows a malicious or compromised HTTP server to degrade availability by returning a numeric header whose value is a very long run of digits.
httpc_handler.erl converts the server-supplied Content-Length with list_to_integer/1 before comparing it against max_body_size, so the size check cannot protect the conversion, and the option defaults to nolimit in any case. The same unbounded conversion appears in httpc_response:format_response/1 for Content-Length and in httpc_response:get_ms_from_retry_after/1 for Retry-After, which is guarded only by a check that the first character is a digit. A value of up to roughly 1.26 million digits converts successfully and costs the requesting process hundreds of milliseconds of arbitrary-precision arithmetic per response. The conversion function is documented to accept integers of any size, so bounding the input is the caller's responsibility.
This issue affects OTP from OTP 17.0 before OTP 27.3.4.17, from OTP 28.0 before OTP 28.5.0.6, and from OTP 29.0 before OTP 29.0.6, corresponding to inets from 5.10 before 9.3.2.7, from 9.4 before 9.6.2.3, and from 9.7 before 9.7.2. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 47% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OT
OTP · Erlang
17.0 before 27.3.4.17; 28.0 before 28.5.0.6; 29.0 before 29.0.6; 5.10 before 9.3.2.7; 9.4 before 9.6.2.3; 9.7 before 9.7.2; +1 more · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-71562
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-71562
cna.erlef.org
https://cna.erlef.org/cves/CVE-2026-71562.html
github.com
https://github.com/erlang/otp/commit/aba0fe8c2d700bf4ac94607cf7f00e53bbe4042d
github.com
https://github.com/erlang/otp/commit/e3be1cfe9f6cedd0cd20d9905e05601dfb31c8aa
github.com
https://github.com/erlang/otp/security/advisories/GHSA-cqx9-9hq6-m8wf
osv.dev
https://osv.dev/vulnerability/EEF-CVE-2026-71562
www.erlang.org
https://www.erlang.org/doc/system/versions.html#order-of-versions
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