CVE WatchOct 8, 2026

CVE-2020-1967

Server or client applications that call the SSL_check_chain() function during or after a TLS 1.3 handshake may crash due to a NULL pointer d

CVSS

7.5

High

EPSS

53.3%

p99

KEV

—

Exploit Today

0-100

Published: Apr 21, 2020 · Last modified: Oct 8, 2026 · CWE-476

EPSS · 30d

53.3%EPSS · 30 days53.3%

2026-09-212026-10-19

Technical description

Server or client applications that call the SSL_check_chain() function during or after a TLS 1.3 handshake may crash due to a NULL pointer dereference as a result of incorrect handling of the "signature_algorithms_cert" TLS extension. The crash occurs if an invalid or unrecognised signature algorithm is received from the peer. This could be exploited by a malicious peer in a Denial of Service attack. OpenSSL version 1.1.1d, 1.1.1e, and 1.1.1f are affected by this issue. This issue did not affect OpenSSL versions prior to 1.1.1d. Fixed in OpenSSL 1.1.1g (Affected 1.1.1d-1.1.1f).

Official references

Related CVEs

CVECVSSEPSSKEVRExploitTitleMod.

CVE-2026-112405—

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——0Pillow is a Python imaging library. From 12.0.0 until 13.0.0, Pillow's Image.merge() can dereference a null image8 plane. Validation skips the first input band, allowing a 32-bit integer or floating-point image backed by image32 storage to be merged as a narrower multiband image. A crafted IPTC file can reach this path when an application opens and loads it, or a caller can invoke Image.merge() directly with such a first band. This causes a native process crash. This issue is fixed in version 13.0.0.22h CVE-2026-112392—

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——0Pillow is a Python imaging library. Prior to 13.0.0, Pillow's rank-based filters can dereference invalid image storage for a zero-size image. ImagingExpand() allocates a non-empty output and then faults while replicating edges by reading the first pixel from empty input storage; ImagingRankFilter is never reached. An attacker can supply or cause creation of a zero-size image to an application that applies a rank, median, minimum, or maximum filter. This causes a native process crash. This issue is fixed in version 13.0.0.5h CVE-2026-767875.9 MED

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——0The UpdateHub firmware-over-the-air client parses the CoAP probe response with Zephyr's JSON library in z_impl_updatehub_probe() (subsys/mgmt/updatehub/updatehub.c). The decoder treats every descriptor field as optional — json_obj_parse() returns a bitmask of the fields it actually decoded and never fails on a missing one — so a response that omits the "sha256sum" string leaves the corresponding const char * in the zero-initialised struct resp_probe_any_boards / struct resp_probe_some_boards at NULL. Both metadata branches then computed sha256size = strlen(...objects.sha256sum) + 1 before any validation, dereferencing that NULL pointer; the SHA256_HEX_DIGEST_SIZE test that follows operates on a value the bad read has already produced and cannot prevent it. The metadata is supplied entirely by the network peer: probe_cb() accepts the datagram, runs coap_packet_parse() and copies the payload with no token matching and no cryptographic check. With CONFIG_UPDATEHUB_DTLS unset — the default — start_coap_client() uses plain CoAP over UDP on port 5683 with no peer authentication and resolves the server via unauthenticated DNS, so an on-path attacker, a DNS spoofer, or an off-path attacker who wins the race with a forged source address can deliver the malformed metadata. A probe response as simple as "objects":[[{}],[{}]] suffices, and no user interaction is required because updatehub_autohandler() polls on CONFIG_UPDATEHUB_POLL_INTERVAL. When CONFIG_UPDATEHUB_DTLS=y the trigger narrows to a malicious or compromised update server. The primitive is a read at address zero, not a write, so the impact is availability only. On targets where the low address range is unmapped or protected — MMU-based architectures, builds with CONFIG_NULL_POINTER_EXCEPTION_DETECTION_DWT/_MPU/_PMP, TrustZone non-secure images, and SoCs such as nRF54L whose 0x0–0x400 window is unmapped — the load faults and Zephyr's default fatal handler halts the system, giving a remotely re-triggerable denial of service on every poll. On classic Cortex-M targets where the vector table is readable at address zero the walk usually terminates immediately and the request is rejected by the length check, so the outcome is configuration- and SoC-dependent. There is no memory write, and the copied bytes are only compared against the locally computed image hash, so there is no information-disclosure channel. The fix adds an explicit sha256sum == NULL test that returns UPDATEHUB_METADATA_ERROR ahead of the strlen() in both metadata branches. Debug builds (CONFIG_UPDATEHUB_LOG_LEVEL=4) still format the same pointers with %s in a LOG_DBG() loop that runs before the new checks, so that variant remains in debug configurations only.23h CVE-2026-1122595.5 MED

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——0A flaw was found in GIMP. Importing a crafted SBZ palette without a color-model attribute can cause a NULL pointer dereference during string comparison, resulting in denial of service of the GIMP application.23h CVE-2026-1056615.3 MED

8.2%

——2Requesting `/{username}/-/repositories` for an individual user instead of an organization made the organization home handler dereference a nil organization and panic. The request needs no authentication and no special configuration. The server answered with an HTTP 500 error and logged a panic for each request; the fix returns 404 for individual users.23h CVE-2026-1117107.5 HIG

20.3%

——6Netcore NR256CN through 1.5.140116 contains a NULL pointer dereference vulnerability in the Boa web server's user_auth() function that allows unauthenticated attackers to crash the server via a malformed Authorization header. Attackers can send a Basic Authorization value lacking a colon, such as one decoding to a single character, to protected routes like /router/get_user_type.cgi to kill the main Boa process and deny management interface access.1d