# CVE-2026-77014: libsoup integer truncation in HTTP Range processing

Source: https://junglewise.ai/threats/cve-2026-77014-libsoup-integer-truncation-in-http-range-processing  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-20. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-77014 · Severity: medium · CVSS 5.3 · Published 2026-08-20

libsoup is an HTTP client/server library used by many Linux applications and services. A flaw in its handling of HTTP Range requests (used for downloading partial files) causes it to silently omit requested byte ranges when responding to partial-content requests on files larger than 2 GB. An attacker could exploit this to cause incomplete file transfers, potentially delivering corrupted or incomplete data to users.

Technologies: [Gnome Libsoup](https://junglewise.ai/threats/technologies/libsoup). Vendors: [Gnome](https://junglewise.ai/threats/vendors/gnome).

## Quick answers

**Is CVE-2026-77014 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-77014 being exploited in the wild.

**How severe is CVE-2026-77014?** Medium severity, with a CVSS score of 5.3, published 20 August 2026.

**Which products and versions are affected?** Gnome Libsoup <unknown>.

**Is there a fix for CVE-2026-77014?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-77014 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-77014?** Check whether you run Gnome Libsoup at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An integer truncation vulnerability (CWE-197) exists in the sort_ranges() comparator function in soup-message-headers.c. A 64-bit subtraction result is truncated to a 32-bit integer, causing sign flips when range offsets differ by more than INT_MAX. This affects HTTP 206 Partial Content responses for resources larger than ~2 GB. The vulnerability is network-reachable and requires no authentication or user interaction; it only manifests when serving large files. The attacker can cause silent omission of requested byte ranges from server responses. A fix is available in the upstream GNOME libsoup project (merge request #550).

## Affected products

- GNOME libsoup <unknown>

## Timeline

- 2026-08-20: disclosed

## References

- [https://access.redhat.com/downloads/content/package-browser/](https://access.redhat.com/downloads/content/package-browser/)
- [https://access.redhat.com/security/cve/CVE-2026-77014](https://access.redhat.com/security/cve/CVE-2026-77014)

## Related threats

- [libsoup HTTP request smuggling via undrained Expect: 100-continue body](https://junglewise.ai/threats/cve-2026-103399-a-flaw-was-found-in-soupserver-libsoup-when-an-http-1-x-client)
- [libsoup heap buffer overflow in permessage-deflate WebSocket extension](https://junglewise.ai/threats/cve-2026-102560-a-flaw-was-found-in-libsoup-when-the-permessage-deflate)
- [libsoup heap buffer overflow in WebSocket handling](https://junglewise.ai/threats/cve-2026-102558-a-flaw-was-found-in-libsoup-when-max-incoming-payload-size-is)
- [libsoup out-of-bounds read in data-URI base64 decoding](https://junglewise.ai/threats/cve-2026-102555-a-flaw-was-found-in-libsoup-the-soup-uri-decode-data-uri)
- [libsoup heap corruption in WebSocket message reassembly](https://junglewise.ai/threats/cve-2026-102557-a-flaw-was-found-in-libsoup-when-reassembling-fragmented)