# CVE-2026-70405: snmp BER INTEGER decoder applies no size limit to attacker-supplied integer fields

Status: published. Published: 2026-09-01. Updated: 2026-11-11.

Improper Validation of Specified Quantity in Input vulnerability in Erlang/OTP snmp allows a remote attacker to degrade availability by sending an SNMP message containing a BER INTEGER whose length field is arbitrarily large.

snmp_pdus:dec_integer_notag/1 defaults its size limit to infinity, and do_dec_integer_notag/2 then accumulates the value across every declared byte with a recursive shift and bitwise or. Work grows superlinearly in the declared length because each operation acts on a progressively larger bignum. The size-limited variant dec_integer_notag/2 exists but is reached from only one call site, dec_snmp_version/1, which bounds the version field to ten bytes; the request identifier, error status and index, generic and specific trap fields, engine boots and time, and every varbind value decoded by dec_value/1 all use the unbounded form. The decode runs before the PDU is processed, so no valid request is required beyond what the deployment demands to accept the message at all.

This issue affects OTP from OTP 17.0 before OTP 27.3.4.17, OTP 28.5.0.6, and OTP 29.0.6, corresponding to snmp from 4.25.1 before 5.18.2.1, 5.20.2.2, and 5.20.5. Whether OTP before OTP 17.0, corresponding to snmp before 4.25.1, is affected is unknown.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: EEF) — https://github.com/erlang/otp/commit/aba0fe8c2d700bf4ac94607cf7f00e53bbe4042d
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: EEF) — https://github.com/erlang/otp/commit/e3be1cfe9f6cedd0cd20d9905e05601dfb31c8aa

## Affected products and versions

- Erlang / OTP (otp): ≥ 17.0; < * (affected, otp); unaffected at 27.3.4.17; unaffected at 28.5.0.6; unaffected at 29.0.6. Source: CNA: EEF
- Erlang / OTP (snmp): ≥ 4.25.1; < * (affected, otp); unaffected at 5.18.2.1; unaffected at 5.20.2.2; unaffected at 5.20.5. Source: CNA: EEF
- Erlang / OTP (erlang/otp): ≥ 84adefa331c4159d432d22840663c38f155cd4c1; < * (affected, git); unaffected at aba0fe8c2d700bf4ac94607cf7f00e53bbe4042d; unaffected at e3be1cfe9f6cedd0cd20d9905e05601dfb31c8aa; ≥ aba0fe8c2d700bf4ac94607cf7f00e53bbe4042d; < * (unaffected, git); ≥ e3be1cfe9f6cedd0cd20d9905e05601dfb31c8aa; < * (unaffected, git). Source: CNA: EEF

## Severity and prioritization

- CVSS 4.0: 6.3 (medium); CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N; source: CNA: EEF

- CISA KEV: No listing in collected sources

- EPSS: 0.71% as of 2026-11-10; percentile 53.84%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-1284

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/erlang/otp/security/advisories/GHSA-q7cq-pfgf-5hr7 (CNA: EEF; vendor-advisory, related)

- https://cna.erlef.org/cves/CVE-2026-70405.html (CNA: EEF; related)

- https://osv.dev/vulnerability/EEF-CVE-2026-70405 (CNA: EEF; related)

- https://www.erlang.org/doc/system/versions.html#order-of-versions (CNA: EEF; x_version-scheme)

- https://github.com/erlang/otp/commit/aba0fe8c2d700bf4ac94607cf7f00e53bbe4042d (CNA: EEF; patch)

- https://github.com/erlang/otp/commit/e3be1cfe9f6cedd0cd20d9905e05601dfb31c8aa (CNA: EEF; patch)

## Provenance

- CNA: EEF: https://www.cve.org/CVERecord?id=CVE-2026-70405; retrieved 2026-11-11; source updated 2026-11-11

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-70405; retrieved 2026-11-11; source updated Not reported

Revision: 1728c0ca3054b970ee750612a97222f82847f6e140fcf05fe7322ad28cfe7374

Canonical: https://y2.dev/cve/CVE-2026-70405

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