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

> Remote attackers can cause denial of service in Erlang OTP SNMP applications by sending messages with oversized BER integer fields, requiring an upgrade to patched versions.

- **Severity:** Medium 6.3 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Sep 2026
- **Updated:** 8 Sep 2026
- **Also known as:** AZL-98472, DEBIAN-CVE-2026-70405, EEF-CVE-2026-70405, GHSA-q7cq-pfgf-5hr7, UBUNTU-CVE-2026-70405

## What is CVE-2026-70405?

CVE-2026-70405 is a medium-severity denial of service vulnerability in Erlang OTP, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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, from OTP 28.0 before OTP 28.5.0.6, and from OTP 29.0 before OTP 29.0.6, corresponding to snmp from 4.25.1 before 5.18.2.1, from 5.19 before 5.20.2.2, and from 5.20.3 before 5.20.5. Whether OTP before OTP 17.0, corresponding to snmp before 4.25.1, is affected is unknown.

Weakness: CWE-1284 (Improper Validation of Specified Quantity in Input)

## Which versions are affected by CVE-2026-70405?


## How do I fix CVE-2026-70405?

Upgrade to a fixed version.

## Is CVE-2026-70405 being exploited?

There is no known exploitation of CVE-2026-70405 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-70405 and fix it if it is affected.

What it is: CVE-2026-70405 is a medium-severity denial of service vulnerability in Erlang OTP, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-70405 in the wild and no public exploit code.

Affected product: Erlang OTP. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-70405/ (Markdown: https://insights.sbomify.com/CVE-2026-70405/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-70405
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-70405
- OSV: https://osv.dev/vulnerability/CVE-2026-70405

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-70405/
Summaries are generated and may contain mistakes; the official description above is the record.