CVE-2026-87776 compression vulnerable to Denial of Service via memory leak on premature response close
A remote attacker can crash the server by repeatedly aborting compressed connections, causing a memory leak in the compression middleware.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-87776?
CVE-2026-87776 is a high-severity denial of service vulnerability in compression, published on 11 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
compression is a Node.js and Express compression middleware. In versions before 1.8.2, when a client aborts the connection while a compressed response is still being sent, the zlib stream created to compress that response is never destroyed, so each aborted compressed response leaks its native zlib memory. A remote unauthenticated attacker can repeatedly open requests and disconnect early, exhausting the available memory and crashing the server. All applications using compression are affected. The issue is fixed in compression 1.8.2, and users should upgrade to 1.8.2 or later.
Which versions are affected by CVE-2026-87776?
2 open source packages ship an affected version, including compression.
| Package | Affected | Fixed in |
|---|---|---|
compression npm | All versions | 1.8.2 |
compression npm | All versions | 1.8.2 |
How do I fix CVE-2026-87776?
Upgrade compression to 1.8.2 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-87776 being exploited?
There is no known exploitation of CVE-2026-87776 in the wild and no public exploit code.
Sources
Also known as AZL-101778, CLEANSTART-2026-IQ33916, CLEANSTART-2026-WT34864, CLSA-2026-1791278863, CLSA-2026-1792473493, CLSA-2026-1792473778 and 18 more.