Out-of-Bounds Read in Openssl (CVE-2026-84782)
Summary
Vulnerability in Openssl (CVE-2026-84782). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
Issue summary: The DTLS retransmission logic does not correctly handle
a handshake message write that is suspended part-way through.
The retransmitted message can be read past the message buffer and
the retransmission overwrites the internal state the suspended write
needs to resume correctly.
Impact summary: The retransmitted message can disclose a heap memory
to the peer as plaintext handshake data or cause a crash and a Denial
of Service when the read reaches an unmapped memory region.
CWE: CWE-125: Out-of-bounds Read
Description: DTLS handshake messages can be written out in multiple
fragments, and a write can suspend mid-message (returning WANT_WRITE)
if the underlying transport temporarily cannot accept more data. While
such a write is suspended, the DTLS retransmission timer may
independently fire and ask the retransmission logic to resend an
earlier, already-acknowledged-as-sent message from its retransmit
queue.
The retransmission logic reused the same internal buffer and position
tracking as the message that was still being written, without
resetting the position back to the start of the message being
retransmitted. As a result the retransmission was read starting from
wherever the suspended write had left off, producing a mislabelled
message whose body was leftover bytes from the other, larger message
still in flight - content that was never meant to be sent at that
point, and which could run past the end of the allocated buffer.
Separately, even when the retr…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-84782 has been found in Openssl.
Risk of unauthorized operations or information disclosure. CVSS score: 8.2/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Openssl CVE-2026-84782" on the vendor's site.
CVE-2026-84782 (Openssl) — CWE-125 / CVSS v3 8.2
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Out-of-bounds read (CWE-125) exists in Openssl.
Check the vendor advisory for the affected versions of Openssl.
Severity: High (CVSS 8.2/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Openssl' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'Openssl' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
Opensslを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Alpine Linux ALPINE-CVE-2026-84782 openssl Fixed in: 3.3.7-r2
References
- patch openssl-security@openssl.org
- patch openssl-security@openssl.org
- patch openssl-security@openssl.org
- patch openssl-security@openssl.org
- patch openssl-security@openssl.org
- web nvd.nist.gov
- web github.com