Vulnerability in rsync (DEBIAN-CVE-2026-44510)

Summary

Vulnerability in rsync (DEBIAN-CVE-2026-44510). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 3.4.3+ds1-1 or later.

Original description

The description as published by the source.

Rsync is a file-copying tool that uses a delta-transfer algorithm to synchronize remote and local files. In versions prior to 3.4.3, the receiver-side out-of-bounds array read in rsync's recv_files() lets a malicious rsync server (or any peer acting in the sender role) deterministically crash any rsync client that pulls from it. The trigger is fully wire-protocol-level, requires no special options on the victim, and works for both rsync:// URLs and remote-shell pulls; since inc_recurse is the protocol-30+ default, any client doing a normal recursive pull against an attacker-controlled URL is exposed. A malicious server sets CF_INC_RECURSE, sends a flist whose first sorted entry is not the leading "." directory (causing parent_ndx to be set to -1), then sends a transfer record with ndx = 0 and an iflag omitting ITEM_TRANSFER, causing the receiver to read 8 bytes before the allocated pointer array and dereference the result in f_name(). The impact is crash-only: the out-of-bounds read lands in glibc mmap chunk metadata and dereferences to an unmapped low address, producing a SEGV that cannot be leveraged into an exploit (confirmed on glibc x86-64 Linux; non-glibc allocators not audited). This issue is fixed in version 3.4.3.

Source: OSV.dev (Open Source Vulnerabilities) OSV

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 DEBIAN-CVE-2026-44510 has been found in rsync.
Risk of unauthorized operations or information disclosure.
What to do: upgrade rsync to 3.4.3+ds1-1 or later.
If unsure, ask your IT team or search "rsync DEBIAN-CVE-2026-44510" on the vendor's site.

DEBIAN-CVE-2026-44510 (rsync)
Attack vector: remote (network-reachable) / unauthenticated
Patched: 3.4.3+ds1-1 — apply immediately
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.

❓ What is the problem

A vulnerability (unclassified) exists in rsync.

📍 Affected scope

Check the vendor advisory for the affected versions of rsync.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 3.4.3+ds1-1.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'rsync' . 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

1
Identify exposure identify
```
grep -r 'rsync' . | 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 rsync を grep し、稼働しているサービス・バージョンを把握する。
2
Apply patch patch
```
Upgrade rsync to 3.4.3+ds1-1
```
ステージング環境で 3.4.3+ds1-1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
3
Post-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。

Affected packages

Debian:11 rsync

[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]

Debian:12 rsync

[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]

Debian:13 rsync

[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]

Debian:14 rsync

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.4.3+ds1-1"}]}]

References

advisory security-tracker.debian.org